Increasing the response of PIN photodiodes to the ultraviolet

Solid state device uses sapphire windows and avoids coatings which absorb ultraviolet radiation and ultimately alter detector geometry. Ultimate solution for ultraviolet response is geometry with maximum peripheral area and horizontal field structure to draw out photon induced current carriers

A Toy Model of the M5-brane: Anomalies of Monopole Strings in Five Dimensions

We study a five-dimensional field theory which contains a monopole (string) solution with chiral fermion zero modes. This monostring solution is a close analog of the fivebrane solution of M-theory. The cancellation of normal bundle anomalies parallels that for the M-theory fivebrane, in particular, the presence of a Chern-Simons term in the low-energy effective U(1) gauge theory plays a central role. We comment on the relationship between the the microscopic analysis of the world-volume theory and the low-energy analysis and draw some cautionary lessons for M-theory.Comment: 32 pages, LaTe

Shear Force Fiber Spinning: Process Parameter and Polymer Solution Property Considerations

For application of polymer nanofibers (e.g., sensors, and scaffolds to study cell behavior) it is important to control the spatial orientation of the fibers. We compare the ability to align and pattern fibers using shear force fiber spinning, i.e. contacting a drop of polymer solution with a rotating collector to mechanically draw a fiber, with electrospinning onto a rotating drum. Using polystyrene as a model system, we observe that the fiber spacing using shear force fiber spinning was more uniform than electrospinning with the rotating drum with relative standard deviations of 18% and 39%, respectively. Importantly, the approaches are complementary as the fiber spacing achieved using electrospinning with the rotating drum was ~10 microns while fiber spacing achieved using shear force fiber spinning was ~250 microns. To expand to additional polymer systems, we use polymer entanglement and capillary number. Solution properties that favor large capillary numbers (\u3e50) prevent droplet breakup to facilitate fiber formation. Draw-down ratio was useful for determining appropriate process conditions (flow rate, rotational speed of the collector) to achieve continuous formation of fibers. These rules of thumb for considering the polymer solution properties and process parameters are expected to expand use of this platform for creating hierarchical structures of multiple fiber layers for cell scaffolds and additional applications

Evaluating the structure of research papers: A case study

This paper is triggered by a concern for the methodological soundness of research papers in RE. We propose a number of criteria for methodological soundness, and apply these to a random sample of 37 submissions to the RE'03\ud conference. From this application, we draw a number of conclusions that we claim are valid for a larger sample than just these 37 submissions. Our major observation is that most submissions in our sample are solution-oriented: \ud they present a solution and illustrate it with a problem, rather than search for a solution to a given problem class; and most papers do not analyze why and when a solution works or does not work. We end with discussion of the need to improve the methodological soundness of research papers in RE

Comment on "New Methods for Old Coulomb Few-Body Problems"

In this Comment on the above mentioned paper by F. E. Harris, A. M. Frolov, and V. H. Smith, we briefly review our contributions to development of new methods for solution of the Coulomb four-body problem. We show that our research group, headed by Prof. T. K. Rebane, had a priority in using the fully correlated exponential basis for variational calculations of four-body systems. We also draw attention to the fact that our group subsequently implemented a more advanced method, which uses highly efficient exponential-trigonometric basis functions for solution of the same problem.Comment: Accepted by the International Journal of Quantum Chemistr

An African perspective on the partiality and impartiality debate: Insights from Kwasi Wiredu's moral philosophy

In this article, I attempt to bridge the gap between partiality and impartiality in moral philosophy from an oft-neglected African perspective. I draw a solution for this moral-theoretical impasse between partialists and impartialists from Kwasi Wiredu's, one of the most influential African philosophers, distinction between an ethic and ethics. I show how an ethic accommodates partiality and ethics impartiality. Wiredu's insight is that partialism is not concerned with strict moral issues

Patterns in Open String Field Theory Solutions

In open string field theory the kinetic operator mixes matter and ghost sectors, and thus the ghost structure of classical solutions is not universal. Nevertheless, we have found from numerical analysis that certain ratios of expectation values for states involving pure ghost excitations appear to be universal. We give an analytic expression for these ratios and find good evidence that they are common to all known solutions of open string field theory, including the tachyon vacuum solution, lump solutions and string fields representing marginal deformations. We also draw attention to a close correspondence between the expectation values for the pure matter components in the tachyon vacuum solution and those in the solution of a simpler equation for a ghost number zero string field. Finally we observe that the action of L_0 on the tachyon condensate gives a state that is approximately factorized into a matter and a ghost part.Comment: 21 pages, LaTe