4,245 research outputs found
Applying knowledge management strategies to economic development in sub-Saharan Africa
Sustainability looks to achieve best outcomes for human and natural environments both now and in the indefinite future. It relates to the continuity of economic, social, institutional and environmental aspects of human society, as well as the non-human environment. This paper examines economic development as one aspect of sustainability, with a focus on knowledge management as an economic development strategy. Using Grey’s categories of knowledge management, the authors address sustainable economic development in the context of sub-Saharan Africa. Production capability is no longer completely dependent on capital and equipment; information and knowledge assets are increasingly important. In this information economy, success comes from harnessing the information and knowledge of a community. Such “indigenous knowledge,” local and often tacit, exists in every community, every region and every country. This knowledge is useful in identifying new entrepreneurial opportunities, as well as for sustaining and advancing local businesses. Sub-Saharan Africa provides an excellent case study. No other region of the world is in more dire need of development. The 700 million people in this area face tremendous challenges, including the world’s highest incidence of HIV/AIDS, deep poverty, unemployment, political instability, and a host of related problems. Key factors for using knowledge management as an economic development strategy in the region will include ICT (Information and Communication Technologies) literacy; uncovering and developing local intellectual assets; capturing tacit knowledge; internal and external knowledge sharing; and managing political, social and technological barriers. Other specific recommendations include promoting ICT literacy through training programs; leveraging internet and email technologies for community building; investing financial resources in R & D; and developing metrics for outcome assessment.Keywords: Knowledge management, economic development, sub-Saharan Africa
Development of material models to predict the crashworthiness of tubes
Metallic tubes have been extensively studied for their crashworthiness as they closely resemble automotive crash rails. Recently, the demand to produce light weight yet safer vehicles has led to the need to understand the behaviour of novel materials such as composites, metallic foams and sandwich structures durign a crash. This paper presents a method to predict the crashworthiness of structural components using material modes. The material factors that most affect the crushing response are determined and quantified by developing and validating the crushing of a square tube model in Abaqus. The inputs from the model are used to construct a simple, physically realistic constitutive model and new test methods for predicting the material behaviour at high strain rates using low test speeds. These material models enable a designer to predict the crash behaviour of a structure without the need to perform extensive physical tests, thus reducing the time and cost of development
Low temperature shape relaxation of 2-d islands by edge diffusion
We present a precise microscopic description of the limiting step for low
temperature shape relaxation of two dimensional islands in which activated
diffusion of particles along the boundary is the only mechanism of transport
allowed. In particular, we are able to explain why the system is driven
irreversibly towards equilibrium. Based on this description, we present a
scheme for calculating the duration of the limiting step at each stage of the
relaxation process. Finally, we calculate numerically the total relaxation time
as predicted by our results and compare it with simulations of the relaxation
process.Comment: 11 pages, 5 figures, to appear in Phys. Rev.
Numerical study of domain coarsening in anisotropic stripe patterns
We study the coarsening of two-dimensional smectic polycrystals characterized
by grains of oblique stripes with only two possible orientations. For this
purpose, an anisotropic Swift-Hohenberg equation is solved. For quenches close
enough to the onset of stripe formation, the average domain size increases with
time as . Further from onset, anisotropic pinning forces similar to
Peierls stresses in solid crystals slow down defects, and growth becomes
anisotropic. In a wide range of quench depths, dislocation arrays remain mobile
and dislocation density roughly decays as , while chevron boundaries
are totally pinned. We discuss some agreements and disagreements found with
recent experimental results on the coarsening of anisotropic electroconvection
patterns.Comment: 8 pages, 11 figures. Phys. Rev E, to appea
Self-Organized Ordering of Nanostructures Produced by Ion-Beam Sputtering
We study the self-organized ordering of nanostructures produced by ion-beam
sputtering (IBS) of targets amorphizing under irradiation. By introducing a
model akin to models of pattern formation in aeolian sand dunes, we extend
consistently the current continuum theory of erosion by IBS. We obtain new
non-linear effects responsible for the in-plane ordering of the structures,
whose strength correlates with the degree of ordering found in experiments. Our
results highlight the importance of redeposition and surface viscous flow to
this nanopattern formation process.Comment: 4 pages, 2 figure
Profile scaling in decay of nanostructures
The flattening of a crystal cone below its roughening transition is studied
by means of a step flow model. Numerical and analytical analyses show that the
height profile, h(r,t), obeys the scaling scenario dh/dr = F(r t^{-1/4}). The
scaling function is flat at radii r<R(t) \sim t^{1/4}. We find a one parameter
family of solutions for the scaling function, and propose a selection criterion
for the unique solution the system reaches.Comment: 4 pages, RevTex, 3 eps figure
Changing shapes in the nanoworld
What are the mechanisms leading to the shape relaxation of three dimensional
crystallites ? Kinetic Monte Carlo simulations of fcc clusters show that the
usual theories of equilibration, via atomic surface diffusion driven by
curvature, are verified only at high temperatures. Below the roughening
temperature, the relaxation is much slower, kinetics being governed by the
nucleation of a critical germ on a facet. We show that the energy barrier for
this step linearly increases with the size of the crystallite, leading to an
exponential dependence of the relaxation time.Comment: 4 pages, 5 figures. Accepted by Phys Rev Let
Structure-property relations of metallic materials with multiscale microstructures
Nanostructured metals have higher strength than those of the coarse grained metals but suffer from the extremely limited ductility. Development of the multiscale microstructures can improve the ductility of these high strength materials due to the introduction of a specific range of grain sizes in micro level. The present work relates the multiscale microstructures in metals to their overall structure properties using a fractal theory and the modified mean-field method, where three microstructural parameters are introduced and thus mechanical properties such as strength and ductility are presented as a function of these microstructural parameters. Meanwhile, with the applications of the finite element method, the multiscale unit cell approach is also critically developed and applied with a focus on predicting the related stress-strain relations of the metals with multiscale microstructures. For verification of these proposed theoretical and numerical algorithms, the mechanical properties of the pure copper with three-grain microstructures are investigated and the results from FEA and theoretical solutions have a reasonable agreement
CE19012
In the southwest of Ireland and the Celtic Sea (ICES Divisions VIIaS, g & j), herring are an important commercial species to the pelagic and polyvalent fleet. For a period in the 1970s and1980s, larval surveys were conducted for herring in this area. However, since 1989, acoustic surveys have been carried out, and currently are the only tuning indices available for this stock. In the Celtic Sea and VIIj, herring acoustic surveys have been carried out since 1989. Since 2004 the survey has been fixed in October and carried out onboard the RV Celtic Explorer. The geographical confines of the annual 21 day survey have been modified in recent years to include areas to the south of the main winter spawning grounds in an effort to identify the whereabouts of winter spawning fish before the annual inshore spawning migration. Spatial resolution of acoustic transects has been increased over the entire south coast survey area. The acoustic component of the survey has been further complemented since 2004 by detailed hydrographic, marine mammal and seabird surveys
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