Robert P. M. Craven

The Stiller-Smith Mechanism: A kinematic analysis

The Stiller-Smith Mechanism provides a unique approach in the use of the rotational characteristics of the cross-slider link of the elliptic trammel. Establishment of the research need and a historical development of the design concept are presented complete with a detailed kinematic analysis. Successful incorporation of the new mechanism is pictorially presented.

Mechanism analysis of a cam driven rotary engine

The plate cam rotary mechanism has application as an IC engine, a pump, a compressor or any similar device. The basic design and operating parameters are explained. The kinematic analysis provides the relationships necessary for a parametric cam track equation. Various parameters are explained and tracks for sinusoidal motion and dwell motion are computed. Various applications are discussed of how this mechanism may be employed. 6 references.

Color measurements of nonhomogeneous colored flat surfaces using a PC-based color camera vision system

This paper presents a test of a vision systems capability to measure consistently the color of blotches and other distinctly colored regions on a flat surface. The system consists of an off-the-shelf color camera, a color-corrected halogen illumination source, and a personal computer equipped with a frame grabber. Correction algorithms to compensate for spatial variations in illumination and sensitivity differences between pixels and the RGB channels are employed along with a calibration procedure to assure consistent measurements of the differently colored regions over a number of samples. A custom conversion of RGB to XYZ color space based on a linear-least squares fit within a certain portion of the color space was also explored to determine its suitability.

Resonance frequency prediction for the CTHA

The contrawound toroidal helical antenna (CTHA) consists of at least two helices wrapped about a toroidal (donut shaped) core with opposite chirality (handedness) and fed from opposite directions. The CTHA is circularly polarized and nearly isotropic. This paper summarizes the work to date for predicting resonant frequencies of the CTHA. The Numerical Electromagnetics Code (NEC2) is used to generate trend plots of basic parameters and predicted resonant frequencies. Parameters considered include the major diameter of the torus, the minor diameter of the torus, the wire thickness, and the number of helical windings about the torus. A brief dimensional analysis is applied to the trends observed from the computer models to get the first estimate of a predictive resonant frequency model and to reduce the number of studied variables. Experimental data is graphed by various parametric groupings to help determine the underlying relationships. The graphs themselves represent the latest design tool for the CTHA.

An empirical model for a hydrocyclone: Reject rate versus orifice size and pressure ratio

Abstract The parameters that affect the reject ratio of a 35 mm liquid-liquid hydrocyclone in test runs that use water alone to obtain flow data-parameters such as inlet pressure, pressure differential ratio, inlet flow rate and reject orifice diameter are explored. Study of the observed relationships indicates that of the parameters listed, only reject orifice diameter and pressure differential ratio have a direct correlation to a liquid-liquid hydrocyclones reject ratio performance. An equation is presented that uses these two parameters to model the reject ratio performance of several reject orifice sizes. The most accurate model presented uses pressure differential ratio as the parameter for a basic equation form, which has a different set of coefficients for each reject orifice size. The practical application of the resulting relationships is discussed and the analysis presented graphically.