Numerical methods and calculations for droplet flow, heating and ignition

A numerical method was devised and employed to solve a variety of problems related to liquid droplet combustion. The basic transport equations of mass, momentum and energy were formulated in terms of generalized nonorthogonal coordinates, which allows for adaptive griding and arbitrary particle shape. Example problems are solved for internal droplet heating, droplet ignition and high Reynolds number flow over a droplet

Portable random number generators

Computers are deterministic devices, and a computer-generated random number is a contradiction in terms. As a result, computer-generated pseudorandom numbers are fraught with peril for the unwary. We summarize much that is known about the most well-known pseudorandom number generators: congruential generators. We also provide machine-independent programs to implement the generators in any language that has 32-bit signed integers-for example C, C++, and FORTRAN. Based on an extensive search, we provide parameter values better than those previously available.Programming (Mathematics) ; Computers

AVIRIS data characteristics and their effects on spectral discrimination of rocks exposed in the Drum Mountains, Utah: Results of a preliminary study

Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) data collected over a geologically diverse field site and over a nearby calibration site were analyzed and interpreted in efforts to document radiometric and geometric characteristics of AVIRIS, quantify and correct for detrimental sensor phenomena, and evaluate the utility of AVIRIS data for discriminating rock types and identifying their constituent mineralogy. AVIRIS data acquired for these studies exhibit a variety of detrimental artifacts and have lower signal-to-noise ratios than expected in the longer wavelength bands. Artifacts are both inherent in the image data and introduced during ground processing, but most may be corrected by appropriate processing techniques. Poor signal-to-noise characteristics of this AVIRIS data set limited the usefulness of the data for lithologic discrimination and mineral identification. Various data calibration techniques, based on field-acquired spectral measurements, were applied to the AVIRIS data. Major absorption features of hydroxyl-bearing minerals were resolved in the spectra of the calibrated AVIRIS data, and the presence of hydroxyl-bearing minerals at the corresponding ground locations was confirmed by field data

How banks can self-monitor their lending to comply with the equal credit opportunity act

The authors provide a step-by-step discussion of how an individual lender in the United States can self-monitor its loan process for compliance with the Equal Credit Opportunity Act and provide an empirical example for illustration. Along the way, they discuss the problems faced by individual lenders who attempt to self-monitor their lending process and conclude with a discussion of the continuing, constructive role for bank examiners and regulators in this endeavor.Regulation B: Equal Credit Opportunity

Trading institutions and price discovery: the cash and futures markets for crude oil

We provide substantial evidence that the futures market for West Texas Intermediate crude oil increased the short-term volatility of the cash price of crude oil. We show that the variability of prices increased using both published posted prices and transaction prices for producers. This increased volatility in the price of crude oil may reflect information aggregated into the price, an increase the variance of shocks to the price of crude oil, or noise in the futures price that affects the cash price. We present evidence from experiments consistent with the interpretation that information aggregation not feasible in a posted-price market can explain at least part of the increase in variance. This evidence supports the proposition that information not previously aggregated into the cash price for crude oil is at least part of the reason for the greater variability of the cash price after the opening of the futures market and provides at least one example in which a futures market increased the volatility of the cash market, and prices became more efficient.

The phase shift of an ultrasonic pulse at an oil layer and determination of film thickness

An ultrasonic pulse incident on a lubricating oil film in a machine element will be partially reflected and partially transmitted. The proportion of the wave amplitude reflected, termed the reflection coefficient, depends on the film thickness and the acoustic properties of the oil. When the appropriate ultrasonic frequency is used, the magnitude of the reflection coefficient can be used to determine the oil film thickness. However, the reflected wave has both a real component and an imaginary component, and both the amplitude and the phase are functions of the film thickness. The phase of the reflected wave will be shifted from that of the incident wave when it is reflected. In the present study, this phase shift is explored as the film changes and is evaluated as an alternative means to measure oil film thickness. A quas i-static theoretical model of the reflection response from an oil film has been, developed. This model relates the phase shift to the wave frequency and the film properties. Measurements of reflection coefficient from a static model oil film and also from a rotating journal bearing have been recorded. These have been used to determine the oil film thickness using both amplitude and phase shift methods. In both cases, the results agree closely with independent assessments of the oil film thickness. The model of ultrasonic reflection is further extended to incorporate mass and damping terms. Experiments show that both the mass and the internal damping of the oil films tested in this work have a negligible effect on ultrasonic reflection. A potentially v ery useful application for the simultaneous measurement of reflection coefficient amplitude and phase is that the data can be used to negate the need for a reference. The theoretical relationship between phase and amplitude is fitted to the data. An extrapolation is performed to determine the values of amplitude and phase for an infinitely thick layer. This is equivalent to the reference signal determined by measuring the reflection coefficient directly, but importantly does not require the materials to be separated. This provides a simple and effective means of continuously calibrating the film measurement approach

Assessment of cockpit interface concepts for data link retrofit

The problem is examined of retrofitting older generation aircraft with data link capability. The approach taken analyzes requirements for the cockpit interface, based on review of prior research and opinions obtained from subject matter experts. With this background, essential functions and constraints for a retrofit installation are defined. After an assessment of the technology available to meet the functions and constraints, candidate design concepts are developed. The most promising design concept is described in detail. Finally, needs for further research and development are identified