4,117 research outputs found

    Control of construction costs during construction

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    The construction of a major project requires a vast amount of time, money, material and human resources. Proper coordination of these elements into an array of activities is crutial to the success of the project if it is to be built on time and within budget. As technology advances, the complexity of the project increases the resources to build them remain finite, and therefore, the project manager must seek methods to improve control on the construction project. This thesis provides an overall view of the relatively new and rapidly expanding field of cost engineering. Cost engineering may be defined as that field of engineering practice where engineering judgement and experience are utilized in the application of science principles and techniques to the areas of cost estimation and cost control. Cost estimation and cost control will be the main subject of this thesis. Although this area has tremendous impact on the economics of private industries and the goverment, cost estimating and cost control has usually underestimated. Virtually all decisions to construct a facility is based on economics, inturn, the economic study is based on the accuracy of an estimate. Once management has committed itself to the project, cost control protects its decision and holds expenditures within budget by constant monitoring and appraisal of cost performance of those responsible for executing the project. The text will provide the reader with the basic understanding of the nature of construction costs, the types and importance of estimates, budgeting procedures and implementation of a cost control system

    Towards microstructured optical fibre sensors: surface analysis of silanised lead silicate glass

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    While protocols to surface functionalise silica glass platforms are well-established, the surface coating of other glass types have received limited attention. Here we fully characterise the surface attachment of a fluoroionophore on extruded lead silicate glass slides and demonstrate these slides as a model for investigating the surface chemistry in a microstructured optical fibre (MOF). This model system allows the utilization of multiple, complementary surface-sensitive techniques that cannot be used within the internal surface of the fibre structure. In characterising the fluoroionophore attachment, we observe that the fluorescence intensity from fluorescence imaging, the atomic nitrogen percentage measured by X-ray photoelectron spectroscopy (XPS), the carbonyl bond component (287.5 eV) in the XPS high resolution carbon spectrum, and Principal Component Analysis (PCA) of the time-of-flight secondary ion mass spectrometry (ToF-SIMS) data can be used to provide relative quantification of the concentration of an attached fluoroionophore. We also show the first use of ToF-SIMS imaging and depth profiling of the Pb content within a glass substrate to provide information on the coverage provided by the coating and the relative thickness of an organic coating. Combined, these techniques provide a comprehensive picture of the coated glass surface that facilitates fibre sensor development.Herbert T. C. Foo, Heike Ebendorff-Heidepriem, Christopher J. Sumby, Tanya M. Monr

    Charge-ordering, commensurability and metallicity in the phase diagram of layered Na(x)CoO(2)

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    The phase diagram of non-hydrated Na(x)CoO(2) has been determined by changing the Na content x using a series of chemical reactions. As x increases from 0.3, the ground state goes from a paramagnetic metal to a charge-ordered insulator (at x=1/2) to a `Curie-Weiss metal' (around 0.70), and finally to a weak-moment magnetically ordered state (x>0.75). The unusual properties of the state at 1/2 (including particle-hole symmetry at low T and enhanced thermal conductivity) are described. The strong coupling between the Na ions and the holes is emphasized.Comment: 4 pages with 3 figures, changed conten

    Quasi-static Response of a Timoshenko Beam Loaded by an Elastically Supported Moving Rigid Beam

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    The present paper is concerned with the quasi-static response of an elastic beam, loaded by a rigid beam, which is slowly transported along the elastic beam. The elastic beam is modelled as a Timoshenko beam. The present paper provides a limiting case of the model with constant distributed load that is often considered in the study of transported masses. The rigid beam is connected to the Timoshenko beam by means of an interface modelled as a Winkler foundation. We present a non-dimensional study on the influence of the interface stiffness upon the displacement, bending moment and shear force of the Timoshenko beam, when the rigid beam is assumed to suffer a prescribed transverse displacement. Special emphasis is laid on the distribution of pressure transmitted by the interface between the Timoshenko beam and the rigid beam. Considerable pressure concentrations are found to take place and the locations of the maximum bending moments in the Timoshenko beam move towards the ends of the rigid beam

    Interface relaxation in electrophoretic deposition of polymer chains: Effects of segmental dynamics, molecular weight, and field

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    Using different segmental dynamics and relaxation, characteristics of the interface growth is examined in an electrophoretic deposition of polymer chains on a three (2+1) dimensional discrete lattice with a Monte Carlo simulation. Incorporation of faster modes such as crankshaft and reptation movements along with the relatively slow kink-jump dynamics seems crucial in relaxing the interface width. As the continuously released polymer chains are driven (via segmental movements) and deposited, the interface width WW grows with the number of time steps tt, Wtβ,W \propto t^{\beta}, (β0.4\beta \sim 0.4--0.8)0.8), which is followed by its saturation to a steady-state value WsW_s. Stopping the release of additional chains after saturation while continuing the segmental movements relaxes the saturated width to an equilibrium value (WsWrW_s \to W_r). Scaling of the relaxed interface width WrW_r with the driving field EE, WrE1/2W_r \propto E^{-1/2} remains similar to that of the steady-state WsW_s width. In contrast to monotonic increase of the steady-state width WsW_s, the relaxed interface width WrW_r is found to decay (possibly as a stretched exponential) with the molecular weight.Comment: 5 pages, 7 figure

    Improved Composite Table Algorithm for targeting regeneration-recycle water network

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    This work aims to improve the Composite Table Algorithm as a targeting tool for regeneration-recycle water network. It is demonstrated that some problems have the potential to achieve zero liquid discharge. A literature example on a petrochemical plant is used to show the applicability of the proposed method. MATLAB is utilised as a programming tool to facilitate the implementation of the developed method
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