Changes of instability thresholds of rotor due to bearing misalignments

The influence of bearing misalignment upon the dynamic characteristics of statistically indeterminant rotor bearing systems is investigated. Both bearing loads and stability speed limits of a rotor may be changed significantly by magnitude and direction of bearing misalignment. The useful theory of short journal bearings is introduced and simple analytical expressions, governing the misalignment problem, are carried out. Polar plots for the bearing load capacities and stability maps, describing the speed limit in terms of misalignment, are presented. These plots can be used by the designer to estimate deviations between calculation and experimental data due to misalignment effects

Apparatus for precision focussing and positioning of a beam waist on a target

The invention relates to optical focussing apparatus and, more particularly, to optical apparatus for focussing a highly collimated Gaussian beam which provides independent and fine control over the focus waist diameter, the focus position both along the beam axis and transverse to the beam, and the focus angle. A beam focussing and positioning apparatus provides focussing and positioning for the waist of a waisted beam at a desired location on a target such as an optical fiber. The apparatus includes a first lens, having a focal plane f sub 1, disposed in the path of an incoming beam and a second lens, having a focal plane f sub 2 and being spaced downstream from the first lens by a distance at least equal to f sub 1 + 10 f sub 2, which cooperates with the first lens to focus the waist of the beam on the target. A rotatable optical device, disposed upstream of the first lens, adjusts the angular orientation of the beam waist. The transverse position of the first lens relative to the axis of the beam is varied to control the transverse position of the beam waist relative to the target (a fiber optic as shown) while the relative axial positions of the lenses are varied to control the diameter of the beam waist and to control the axial position of the beam waist. Mechanical controllers C sub 1, C sub 2, C sub 3, C sub 4, and C sub 5 control the elements of the optical system. How seven adjustments can be made to correctly couple a laser beam into an optical fiber is illustrated. Prior art systems employing optical techniques to couple a laser beam into an optical fiber or other target simply do not provide the seven necessary adjustments. The closest known prior art, a Newport coupler, provides only two of the seven required adjustments

The Evaluation Of Barrier Option Prices Under Stochastic Volatility

This paperc onsiders the problem o fnumerically evaluating barrier option prices when the dynamics of the underlying are driven by stochastic volatility following the square root process of Heston (1993). We develop a method of lines approach to evaluate the price as well as the delta and gamma of the option. The method is able to effciently handle bothc ontinuously monitored and discretely monitored barrier options and can also handle barrier options with early exercise features. In the latter case, we can calculate the early exercise boundary of an American barrier option in both the continuously and discretely monitored cases.barrier option; stochastic volatility; continuously monitored; discretely monitored; free boundary problem; method of lines; Monte Carlo simulation

A Spatio-temporal Model for Agricultural Yield Prediction

The paper presents a spatio-temporal statistical model of agricultural yield prediction based on spatial mixtures of distributions. The proposed method combines several hierarchical and sequential Bayesian estimation procedures that allow the general problem to be addressed with a series of simpler tasks, providing the required flexibility of the model while decreasing the complexity associated with the large dimensionality of the spatial data sets. The data used for the study are 1970 - 2009 annual Iowa state county level corn yield data. The spatial correlation hypothesis is studied by comparing the alternative models using the posterior predictive criterion under squared loss function.Farm Management,

Joint research with McDonnell Douglas Corporation

Issued as Reports [nos. 1-3], Project no. G-37-61

For the Flock: Impetus for Shepherd Leadership in John 10

Following the prophets’ declarations concerning the need for right-hearted shepherds, the four Gospels portray Jesus as the fulfillment of God’s promise to send a Shepherd to save Israel (Ezek. 34:23). John’s Gospel extends the pastoral imagery of the Old testament, most notably in the Good Shepherd discourse (John 10:1-21). John’s development of the shepherd motif presents Jesus both as the Good Shepherd who will lay down his life for his sheep and as the model after whom other shepherds ought to pattern their leadership. contrary to contemporary conversations concerning christian leadership, though, John’s gospel places greater emphasis on the shepherd’s heart motivation than it does on the practical tactics of his leadership. In the Good Shepherd discourse, Jesus demonstrates that genuine shepherd leadership is indicated primarily by a singular concern for the sheep entrusted to the leader’s care. this article demonstrates that emphasis by examining the shepherd imagery portrayed in John 10

Analysis of EM scattering from curved surfaces

Issued as Progress report, Report, and Final report, Project no. G-37-641Library lacks diskett

Locally one dimensional numerical methods for multidimensional free surface problems

Issued as Progress reports no. [1-4], and Final report, Project no. G-37-61