Closed loop analysis of a triangular wave generator (Closed loop system analysis of triangular wave generator consisting of integrator, on-off element with hysteresis and multiplier)

Applications requiring a triangular wave generator that gives a symmetrical output, and the frequency of which can be varied over a wide range by an external input voltage, are many-fold. The theoretical basis for the design of such a system has been presented here, based on the closed loop analysis. A scheme for practical implementation that uses integrated circuit blocks, is also provided. The circuit described by Klein and Hagenbeuk (1907) for this purpose, however, uses only discrete components

Investigating the Site of Newton's Laboratory in Trinity College, Cambridge

It is not generally known that over the course of some thirty years, Isaac Newton carried out around four hundred chemical experiments in a private laboratory located in the walled garden immediately below his rooms in Trinity College, Cambridge. The exact location of his laboratory has long been a source of conjecture and this article describes a survey undertaken to determine both the possible site of the laboratory as well as that of the rubbish pit in which Newton would have disposed of the waste materials generated in his chemical experiments. The results are believed to be of sufficient interest to justify continuation of the investigation

Levi Pennington Writing to Brother Parker, May 19, 1946

Levi Pennington writing to his brother Parker, talking about an interesting speaker who came to the Rotary Club named Caldwell, who denounced the O.P.A. while being humorous. Pennington talks about other parts of life as well.https://digitalcommons.georgefox.edu/levi_pennington/1055/thumbnail.jp

Nash Problem for quotient surface singularities

We give an affirmative answer to Nash Problem for quotient surface singularities, in particular for the icosahedral singularity $E_8$.Comment: 25 pages with 5 figures. This is part of the author\'s PhD thesi

On the Properties of Energy Stable Flux Reconstruction Schemes for Implicit Large Eddy Simulation

We begin by investigating the stability, order of accuracy, and dispersion and dissipation characteristics of the extended range of energy stable flux reconstruction (E-ESFR) schemes in the context of implicit large eddy simulation (ILES). We proceed to demonstrate that subsets of the E-ESFR schemes are more stable than collocation nodal discontinuous Galerkin methods recovered with the flux reconstruction approach (FRDG) for marginally-resolved ILES simulations of the Taylor-Green vortex. These schemes are shown to have reduced dissipation and dispersion errors relative to FRDG schemes of the same polynomial degree and, simultaneously, have increased CourantFriedrichs-Lewy (CFL) limits. Finally, we simulate turbulent flow over an SD7003 aerofoil using two of the most stable E-ESFR schemes identified by the aforementioned Taylor-Green vortex experiments. Results demonstrate that subsets of E-ESFR schemes appear more stable than the commonly used FRDG method, have increased CFL limits, and are suitable for ILES of complex turbulent flows on unstructured grids

The propagation of technology management taxonomies for evaluating investments in information systems

To provide managers with a critical insight into the management of new technology, this paper uses a case study research strategy to examine the technology management experiences of a leading UK manufacturing organization during its adoption of a vendor-supplied Manufacturing Resource Planning information system.<br /

A novel 90xB0; phase shifter for square waves

In the field of electronic instrumentation there are many applications where a circuit is needed to shift the use of square waves by 90xB0;. In this paper a simple and novel scheme to achieve this end is proposed. This circuit, along with a modulo-two-adder, also enables one to obtain the double frequency component of the original input square wave. It is thus possible to have frequency multiplication by powers of two by cascading such circuits in tandem. The entire circuitry, excepting the time averaging capacitors, can be either13; integrated in one chip or fabricated in tins module form

Visibility studies in archaeology: a review and case study

This paper describes the history and current state of archaeological visibility studies. The first part is a survey of both GIS (geographic information systems) and non-GIS studies of visibility by archaeologists, which demonstrates how advances in GIS visibility studies have tended to recapitulate, albeit over a compressed timescale, theoretically driven developments in non-GIS studies. The second part presents an example of the kind of methodological development required for the use of GIS to contribute to the agenda set by certain strands of a more humanistic archaeology. An algorithm developed to retrieve various summaries of the inclination at which points on the horizon are visible from a specified viewpoint was applied to nineteen recumbent stone circles in the Grampian region of Scotland. The results suggest that these summaries provide a useful tool for 'unpacking' what archaeologists mean when they claim that the topographic setting of certain stone circles creates an 'impression of circularity'

Multisymplectic formulation of fluid dynamics using the inverse map

We construct multisymplectic formulations of fluid dynamics using the inverse of the Lagrangian path map. This inverse map, the ‘back-to-labels’ map, gives the initial Lagrangian label of the fluid particle that currently occupies each Eulerian position. Explicitly enforcing the condition that the fluid particles carry their labels with the flow in Hamilton's principle leads to our multisymplectic formulation. We use the multisymplectic one-form to obtain conservation laws for energy, momentum and an infinite set of conservation laws arising from the particle relabelling symmetry and leading to Kelvin's circulation theorem. We discuss how multisymplectic numerical integrators naturally arise in this approach.</p