1,225 research outputs found
Sen and the art of educational maintenance: evidencing a capability, as opposed to an effectiveness, approach to schooling
There are few more widely applied terms in common parlance than ‘capability’. It is used (inaccurately) to represent everything from the aspiration to provide opportunity to notions of innate academic ability, with everything in between claiming apostolic succession to Amartya Sen, who (with apologies to Aristotle) first developed the concept. This paper attempts to warrant an adaptation of Sen’s capability theory to schooling and schooling policy, and to proof his concepts in the new setting using research involving 100 pupils from 5 English secondary schools and a schedule of questions derived from the capability literature. The findings suggest that a capability approach can provide an alternative to the dominant Benthamite school effectiveness paradigm, and can offer a sound theoretical framework for understanding better the assumed relationship between schooling and well-being
Aspects of Dielectric Breakdown in a Model for Disordered Nonlinear Composites
We study dielectric breakdown in a semi-classical bond percolation model for
nonlinear composite materials introduced by us and the related breakdown
exponent near the percolation threshold in two dimensions. The breakdown
exponent after doing finite size scaling analysis is found to be
1.42. We discuss in detail the differences in our model from the traditional
models for dielectric breakdown and argue that our result seems to be different
from the standard result of 4/3 obtained in the previous models.Comment: 20 pages, LaTex file (6 postscript figures included
Adsorbent Carbon Fabrics : New Generation Armour for Toxic Chemicals
Activated carbon in the form of a regular fabric obtained using viscose rayon precursor is a new generation adsorbent material having superior sorptional properties and is finding varied defence applications. Carbonisation and activation mechanisms and properties and applications of adsorbent carbort fibres made from viscose rayon precursor are reviewed in this paper
Common origin of no-cloning and no-deleting principles - Conservation of information
We discuss the role of the notion of information in the description of
physical reality. We consider theories for which dynamics is linear with
respect to stochastic mixing. We point out that the no-cloning and no-deleting
principles emerge in any such theory, if law of conservation of information is
valid, and two copies contain more information than one copy. We then describe
the quantum case from this point of view.Comment: This paper is dedicated to Asher Peres on the occasion of his
seventieth birthda
An optimal network for passenger traffic
The optimal solution of an inter-city passenger transport network has been
studied using Zipf's law for the city populations and the Gravity law
describing the fluxes of inter-city passenger traffic. Assuming a fixed value
for the cost of transport per person per kilometer we observe that while the
total traffic cost decreases, the total wiring cost increases with the density
of links. As a result the total cost to maintain the traffic distribution is
optimal at a certain link density which vanishes on increasing the network
size. At a finite link density the network is scale-free. Using this model the
air-route network of India has been generated and an one-to-one comparison of
the nodal degree values with the real network has been made.Comment: 5 pages, 4 figure
On a coordinate independent description of string worldsheet theory
We study worldsheet conformal invariance for bosonic string propagating in a
curved background using the hamiltonian formalism. In order to formulate the
problem in a background independent manner we first rewrite the worldsheet
theory in a language where it describes a single particle moving in an
infinite-dimensional curved spacetime. This language is developed at a formal
level without regularizing the infinite-dimensional traces. Then we adopt
DeWitt's (Phys.Rev.85:653-661,1952) coordinate independent formulation of
quantum mechanics in the present context. Given the expressions for the
classical Virasoro generators, this procedure enables us to define the
coordinate invariant quantum analogues which we call DeWitt-Virasoro
generators. This framework also enables us to calculate the invariant matrix
elements of an arbitrary operator constructed out of the DeWitt-Virasoro
generators between two arbitrary scalar states. Using these tools we further
calculate the DeWitt-Virasoro algebra in spin-zero representation. The result
is given by the Witt algebra with additional anomalous terms that vanish for
Ricci-flat backgrounds. Further analysis need to be performed in order to
precisely relate this with the beta function computation of Friedan and others.
Finally, we explain how this analysis improves the understanding of showing
conformal invariance for certain pp-wave that has been recently discussed using
hamiltonian framework.Comment: 32 pages, some reorganization for more elaborate explanation, no
change in conclusio
Frequency-dependent (ac) Conduction in Disordered Composites: a Percolative Study
In a recent paper [Phys. Rev. B{\bf57}, 3375 (1998)], we examined in detail
the nonlinear (electrical) dc response of a random resistor cum tunneling bond
network (, introduced by us elsewhere to explain nonlinear response of
metal-insulator type mixtures). In this work which is a sequel to that paper,
we consider the ac response of the -based correlated () model.
Numerical solutions of the Kirchoff's laws for the model give a power-law
exponent (= 0.7 near ) of the modulus of the complex ac conductance at
moderately low frequencies, in conformity with experiments on various types of
disordered systems. But, at very low frequencies, it gives a simple quadratic
or linear dependence on the frequency depending upon whether the system is
percolating or not. We do also discuss the effective medium approximation
() of our and the traditional random network model, and discuss
their comparative successes and shortcomings.Comment: Revised and reduced version with 17 LaTeX pages plus 8 JPEG figure
Evaluation of Chemical Protective Clothing: A Comparative Study of Breakthrough Times with Sulphur Mustard and a Simulant, 1,3-Dichloropropane
Carbon-coated non-woven fabrics were evaluated against vesicant sulphur mustard and l,3-dichloropropane (DCP). Breakthrough times of these chemicals were compared andfitted in a linear equation. A correlation, better than 95 per cent was obtained. It is recommended that DCP be used in the valuation and quality control of fabric in the chemical protective clothing manufacturing industries to reduce the exposure and risks of handling lethal chemicals. However,-the clothing may be challenged with actual CW agents to determine their protective potentials, in the laboratory. Diffusion coefficients for DCP were also computed from the breakthrough data for carbon-coated fabric of different grades
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