Polynomial manipulator AP-168

Linear Systems Design Evaluation Program, AP-168 combines the many different analysis techniques used to evaluate and manipulate polynomials. The single program is a pseudo instruction abstraction. It allows the user to enter polynomials of the laplace operators and to manipulate them freely

The Improbability of Positivism

Ronald Dworkin’s contributions to legal philosophy have been subject to severe criticism in recent years. Other legal philosophers call his arguments “deflected or discredited,” laced with “philosophical confusions,” and “deeply embedded” mistakes. As Brian Leiter writes, “[t]he only good news in the story about Dworkin’s impact on law and philosophy is that most of the field declined to follow the Dworkinian path . . . .” This Article endeavors to show that, far from an effort beset with primitive errors, Dworkin’s challenge to legal positivism in the opening pages of his seminal work was neither misguided nor trivial. Rather, Dworkin’s challenge remains as important and thought-provoking today as it was when he first set it down. His challenge, though straightforward, has never been satisfactorily answered. Rather than grapple with Dworkin’s argument, legal philosophers have either misunderstood or trivialized his insights in the decades since. But there is a reason H.L.A. Hart, one of Dworkin’s examiners at Oxford, saved his jurisprudence examination before ever having reason to believe that Dworkin would become the primary opponent to legal positivism. Hart’s challenge—the argument from theoretical disagreement—still burns bright nearly a quarter-century on. Furthermore, this Article seeks to explain why legal positivism’s inability to preserve the face value of theoretical disagreement makes it improbable that legal positivism offers an adequate descriptive account of the nature of law. It also endeavors to outline why this deficiency is so immensely important. To accept the legitimacy of theoretical disagreement is accept that to know what the law is one must know something about the moral and political culture in which that law resides

Development of EM-CCD-based X-ray detector for synchrotron applications

A high speed, low noise camera system for crystallography and X-ray imaging applications is developed and successfully demonstrated. By coupling an electron-multiplying (EM)-CCD to a 3:1 fibre-optic taper and a CsI(Tl) scintillator, it was possible to detect hard X-rays. This novel approach to hard X-ray imaging takes advantage of sub-electron equivalent readout noise performance at high pixel readout frequencies of EM-CCD detectors with the increase in the imaging area that is offered through the use of a fibre-optic taper. Compared with the industry state of the art, based on CCD camera systems, a high frame rate for a full-frame readout (50 ms) and a lower readout noise (<1 electron root mean square) across a range of X-ray energies (6–18 keV) were achieved

Do Natural Disasters Stimulate Individual Saving? Evidence from a Natural Experiment in a Highly Developed Country

While various empirical studies have found negative growth-effects of natural disasters, little is yet known about the microeconomic channels through which disasters might affect short- and especially long-term growth. This paper contributes to filling this gap in the literature by studying how natural disasters affect individual saving decisions. This study makes use of a natural experiment created by the European Flood of August 2002. Using micro data from the German Socio-Economic Panel that we combine with geographic flood data, we compare the savings behavior of affected and non-affected individuals by using a difference-in-differences approach. Our empirical results indicate that natural disasters depress individual saving decisions, which might be the consequence of a Samaritan's Dilemma

Do Natural Disasters Stimulate Individual Saving? Evidence from a Natural Experiment in a Highly Developed Country

While various empirical studies have found negative growth-effects of natural disasters, little is yet known about the microeconomic channels through which disasters might affect short- and especially long-term growth. This paper contributes to filling this gap in the literature by studying how natural disasters affect individual saving decisions. This study makes use of a natural experiment created by the European Flood of August 2002. Using micro data from the German Socio-Economic Panel that we combine with geographic flood data, we compare the savings behavior of affected and non-affected individuals by using a difference-in-differences approach. Our empirical results indicate that natural disasters depress individual saving decisions, which might be the consequence of a Samaritan`s Dilemma

Apparent phonon side band modes in pi-conjugated systems: polymers, oligomers and crystals

The emission spectra of many pi-conjugated polymers and oligomers contain side-band replicas with apparent frequencies that do not match the Raman active mode frequencies. Using a time dependent model we show that in such many mode systems, the increased damping of the time dependent transition dipole moment correlation function results in an effective elimination of the vibrational modes from the emission spectrum; subsequently causing the appearance of a regularly spaced progression at a new apparent frequency. We use this damping dependent vibrational reshaping to quantitatively account for the vibronic structure in the emission spectra of pi-conjugated systems in the form of films, dilute solutions and single crystals. In particular, we show that by using the experimentally measured Raman spectrum we can account in detail for the apparent progression frequencies and their relative intensities in the emission spectrum.Comment: Presented in "Optical Probes 2005", Bangalore, Indi

SHARC: Space Habitat, Assembly and Repair Center

Integrated Space Systems (ISS) has taken on the task of designing a Space Habitat, Assembly and Repair Center (SHARC) in Low Earth Orbit to meet the future needs of the space program. Our goal is to meet the general requirements given by the 1991/1992 AIAA/LORAL Team Space Design competition with an emphasis on minimizing the costs of such a design. A baseline structural configuration along with preliminary designs of the major subsystems was created. Our initial mission requirements, which were set by AIAA, were that the facility be able to: support simultaneous assembly of three major vehicles; conduct assembly operations and minimal extra vehicular activity (EVA); maintain orbit indefinitely; and assemble components 30 feet long with a 10 foot diameter in a shirtsleeve environment

Using Curb and Figure-Eight Skills Tests to Compare Maneuverability of the user assistant team in the Motivation Rough Terrain Wheelchair and the Whirlwind RoughRider Wheelchair

ABSTRACT Some wheelchair users who cannot self-propel use powered chairs. In less-resourced settings powered chairs may not be available and users may rely on assistants to push them. In these environments, obstacles similar to curbs are common and living spaces are small1,2. Efficiency and maneuverability are two key aspects of wheelchair performance in such settings1 .Validated skills tests for measuring wheelchair performance over obstacles and in tight spaces include timed exercises involving curbs and figure-eight patterns3. We hypothesized that some chairs designed for less-resourced settings would be easier than others for assistants to push in tight spaces and over curbs. College-aged participants (n=29) serving as assistants completed two three minute skills tests with two models of wheelchairs designed for less-resourced settings, the Motivation Rough Terrain and the Whirlwind RoughRider chair. The two skills tests consisted of three minute timed walk tests (TWT) with each chair on two short tracks, one encompassing a curb and the other in a figure eight around chairs. PolarPro heart rate monitors were used to collect heart rates. Distance traveled was measured and physiological cost index (PCI) was calculated. Subject feedback was obtained through visual analogue scale (VAS) questions and written comments for each exercise. Two-way within subject ANOVA analysis and post hoc paired t-tests were used to evaluate data. Within subject ANOVA indicated that the Motivation chair significantly outperformed the Whirlwind chair in PCI, TWT, and VAS responses. Post hoc paired t-tests of PCI values and VAS responses indicated that the differences between the Motivation and the Whirlwind were significant for both tracks. This data was normal and showed interaction but no crossover. The post hoc t-test analysis of TWT data, however, showed significant difference for the curb but only nearly significant difference for the figure-eight. In the written comments, subjects indicated a preference for the design of the Motivation chair mentioning certain features such as the single front castor wheel and the position of the handle bars. Our data indicates that the Motivation Rough Terrain chair may provide superior mobility to assistants serving people with disabilities in less-resourced settings specifically while maneuvering through tight spaces and over obstacles. Through this research, we hope wheelchair manufacturers will be encouraged to make improvements in wheelchair functionality for assistant pushers in less-resourced settings

The meshing of timing belt teeth in pulley grooves

The work described here has been carried out to obtain a better understanding of the tooth root cracking failure mode of timing belts. Previous work has demonstrated the close dependence of this on the tooth deflections of fully meshed teeth, generated by torque transmission, but has not considered the additional distortions generated in the partially meshed conditions at entry to and exit from a pulley groove. Approximate compatibility and constitutive equations are combined with a rigorous consideration of tooth equilibrium in partial meshing to show how bending moments are generated at both exit from a driven pulley and entry to a driving pulley. Experimentally determined belt lives correlate very well with a combined measure of fully meshed tooth strain and strain due to bending at entry or exit. The analysis also shows that this strain measure reduces with increasing belt tooth stiffness, confirming the importance of a high tooth stiffness for a long belt life. Tooth force variations through the partial meshing cycle have also been predicted and compared with measurements obtained from a special strain gauge instrumented pulley. A greater pulley rotation than is predicted is required for a belt tooth to seat in a pulley groove. There is room for improvement in the modellin