A design research approach

The significance of the design process in determining the success or failure of a product in the market place is becoming increasingly more articulated. Consequently companies are implementing and developing new techniques and tools to support design more effectively. Design research is directed at gaining a greater understanding of design, ultimately to better support it through the development of improved techniques, methods or tools

Advection and Taylor-Aris dispersion in rivulet flow

Motivated by the need for a better understanding of the transport of solutes in microfluidic flows with free surfaces, the advection and dispersion of a passive solute in steady unidirectional flow of a thin uniform rivulet on an inclined planar substrate driven by gravity and/or a uniform longitudinal surface shear stress are analysed. Firstly, we describe the short-time advection of both an initially semi-infinite and an initially finite slug of solute of uniform concentration. Secondly, we describe the long-time Taylor-Aris dispersion of an initially finite slug of solute. In particular, we obtain the general expression for the effective diffusivity for Taylor-Aris dispersion in such a rivulet, and discuss in detail its different interpretations in the special case of a rivulet on a vertical substrate

Rivulet flow of generalized Newtonian fluids

Steady unidirectional gravity-driven flow of a uniform thin rivulet (i.e. a rivulet with small transverse aspect ratio) of a generalised Newtonian fluid down a vertical planar substrate is considered. The parametric solution for any generalised Newtonian fluid whose viscosity can be expressed as a function of the shear rate, and the explicit solution for any generalised Newtonian fluid whose viscosity can be expressed as a function of the extra stress are obtained. These general solutions are used to describe rivulet flow of Carreau and Ellis fluids, highlighting the similarities and differences between the behaviour of these two fluids. In addition, the general behaviour of rivulets of nearly Newtonian fluids and of rivulets with small or large prescribed flux, as well as the behaviour of rivulets of strongly shear-thinning Carreau and Ellis fluids, are also described. It is found that whereas the monotonic dependence of the viscosity of a Carreau fluid on its three non-dimensional parameters and of an Ellis fluid on two of its three non-dimensional parameters leads to the expected dependence of the behaviour of the rivulet on these parameters (namely that increasing the viscosity of the fluid leads to a larger rivulet), the non-monotonic dependence of the viscosity of an Ellis fluid on the non dimensional parameter that measures the degree of shear thinning leads to a more complicated dependence of the behaviour of the rivulet on this parameter. In particular, it is also found that when the maximum extra stress in the rivulet is sufficiently large a rivulet of an Ellis fluid in the strongly shear-thinning limit in which this parameter becomes large comprises two regions with different viscosities. In the general case of non-zero viscosity in the limit of large extra stress the two regions have different constant viscosities, whereas in the special case of zero viscosity in the limit of large extra stress one region has constant viscosity and the other has a non-constant power-law viscosity, leading to a plug-like velocity profile with large magnitude in the narrow central region of the rivulet

Application of remote sensing to state and regional problems

The methods and procedures used, accomplishments, current status, and future plans are discussed for each of the following applications of LANDSAT in Mississippi: (1) land use planning in Lowndes County; (2) strip mine inventory and reclamation; (3) white-tailed deer habitat evaluation; (4) remote sensing data analysis support systems; (5) discrimination of unique forest habitats in potential lignite areas; (6) changes in gravel operations; and (7) determining freshwater wetlands for inventory and monitoring. The documentation of all existing software and the integration of the image analysis and data base software into a single package are now considered very high priority items

Time Reversal to Localise Multiple Partial Discharges in Power Cables

The paper studies the suitability of the electromagnetic time reversal (EMTR) technique to localise multiple sources of partial discharges (PD) in power cables. In particular, the localisation of two PDs in a homogeneous power line is investigated both in the presence or absence of noise. The investigation, which is based on numerical simulations, shows that an EMTR-based PD localisation method is able to localise two PDs occurring simultaneously in a line using only a measurement at one observation point (OP), indiscriminately collecting the direct and reflected signals coming from the two PD sources. The EMTR procedure to localise multiple PD sources, using a Transmission Line Matrix model digital twin for the time reversal simulations, is described and the challenges that must be addressed to develop an EMTR-based device for the on-line location of multiple PDs are discussed

Nearly universal crossing point of the specific heat curves of Hubbard models

A nearly universal feature of the specific heat curves C(T,U) vs. T for different U of a general class of Hubbard models is observed. That is, the value C_+ of the specific heat curves at their high-temperature crossing point T_+ is almost independent of lattice structure and spatial dimension d, with C_+/k_B \approx 0.34. This surprising feature is explained within second order perturbation theory in U by identifying two small parameters controlling the value of C_+: the integral over the deviation of the density of states N(\epsilon) from a constant value, characterized by \delta N=\int d\epsilon |N(\epsilon)-1/2|, and the inverse dimension, 1/d.Comment: Revtex, 9 pages, 6 figure

Beyond the performance gap: reclaiming building appraisal through archival research

Current debates about building performance evaluation often emphasise the ‘performance gap’ between how buildings perform in practice and how performance was envisaged during the design stage. While such debates continue to be dominated by energy considerations, increasing attention is directed towards the subjective experiences of building users in terms of thermal comfort and wellbeing. The latter trends are undoubtedly to be welcomed, but buildings continue to be conceptualised as fixed physical objects rather than entities that are enacted in practice. With the aim of challenging current assumptions, research is described which sought to reclaim the concept of building appraisal as practised by the pioneering architectural practice DEGW. The concept of building appraisal differs from current notions of building performance evaluation in that the point of departure was not the supposedly fixed entity of the building, but the essential fluidity of the occupying organisation and their aspirations in terms of space. Empirical data is derived from archival sources and through extensive interaction with the DEGW diaspora, many of whom remain active at the leading edge of international practice. It is concluded that the continued fixation with the ‘performance gap’ reinforces long-since discredited assumptions of environmental determinism

Electromagnetic time reversal applied to online partial discharge location in power cables: influence of interfering reflections from the cable circuit

In online single-sided partial discharge (PD) location settings, PD reflection patterns are affected by all components present in the cable circuit. This paper describes the performance of electromagnetic time reversal (EMTR) when interfering reflections contribute to the transient waveforms emitted by the PD. The analysed situation refers to a ring main unit (RMU) in the medium voltage (MV) grid where PD recordings are disturbed by signals reflected from the other cables connected to the RMU, potentially affecting the PD location accuracy. We show that the accuracy of EMTRbased location methods is unaffected by such effects

EVALUATING THE EFFECTIVENESS OF THE COURSEWARE DEVELOPMENT PROJECT: PILOT STUDIES

This project involves a comprehensive generalizable and transferable evaluation of the Courseware Development Project (CDP) at Dalhousie University\u27s School of Business Administration. This C$3 million, three-year project is divided into four levels over three time phases. The results of the study of the impact of this unique project are expected to be both relevant and applicable to other universities in Canada and throughout the world. This on-going evaluation of the CDP centers around a systems model where: inputs are divided into drivers and materials; throughputs are the conversion processes on a matrix composed of six parties (faculty, students, staff, administrators, organizational structure and processes, and contributing/participating corporations) as the rows and the four levels of the CDP as the columns; and outputs are divided into manifest and latent variables. Demographic, attitudinal, behavioral, and organizational variables will be used in a time series analysis. Using an action research model over the proposed three-year full study, the researchers will assess which elements Of the project are effective at the end of each year of the evaluation. Based on this information the researchers will keep the effective elements in place for the next year and modify any ineffective elements based on the first year\u27s results and competing theory. This cycle will be repeated after year two. Thus the proposed study will contribute to evaluation methodology as described in this paper by treating simultaneously both a case study and a quasiexperiment of the impact of computers on (business) education. A preliminary description of the effects arising from Level 0, the integration of computers in the business school, and Level 1, courseware development. is given here. The general impact of the project upon faculty, staff, and students is described and preliminary findings are presented

Thin-film flow in helically wound rectangular channels with small torsion

Laminar gravity-driven thin-film flow down a helically-wound channel of rectangular cross-section with small torsion in which the fluid depth is small is considered. Neglecting the entrance and exit regions we obtain the steady-state solution that is independent of position along the axis of the channel, so that the flow, which comprises a primary flow in the direction of the axis of the channel and a secondary flow in the cross-sectional plane, depends only on position in the two-dimensional cross-section of the channel. A thin-film approximation yields explicit expressions for the fluid velocity and pressure in terms of the free-surface shape, the latter satisfying a non-linear ordinary differential equation that has a simple exact solution in the special case of a channel of rectangular cross-section. The predictions of the thin-film model are shown to be in good agreement with much more computationally intensive solutions of the small-helix-torsion Navier–Stokes equations. The present work has particular relevance to spiral particle separators used in the mineral-processing industry. The validity of an assumption commonly used in modelling flow in spiral separators, namely that the flow in the outer region of the separator cross-section is described by a free vortex, is shown to depend on the problem parameters