Self-erecting reflector Patent

Antenna design with self erecting mesh reflecto

Ecology of Plant Distribution on the Salt-Deserts of Utah

The reciprocal effects of vegetation and soils have long been a subject of speculation and conjecture. In the management of any natural land area the problem of interpreting vegetational expression is especially important. The effects of native vegetation on soils and the effects of the soil on the vegetation have been studied and observed for many years. The arid-desert range lands have been studied and observed for many years. The arid-desert range lands have been studied least and as a result are not well understood. As human populations increase there will be additional need for agricultural production, and these lands may be put to higher use, perhaps even to irrigated crop production. Basic to increasing the productivity of these lands is an understanding of the vegetation they are now supporting, what they supported prior to their use by domestic livestock, and why the present vegetation grows to the exclusion of other vegetation types

An expert system for project controls in construction management

In this paper, I describe an expert project control system for construction management. The purpose of the project is to develop methods and strategies for expert system based planning, scheduling, chronicling and analysis for construction management. Planning defines the actions required to accomplish a goal? scheduling links the plan into a frame of time? chronicling is monitoring job performance and analysis defines reevaluation of the plan as conditions change. Conditions are modeled as constraints and will be coded as rules. As conditions change, constraints must be dynamically modified by the system to accommodate the changes. The research is a combination of three related areas: a. Domain dependent hierarchical planning techniques. b. Model-based planning/scheduling techniques developed for the job-shop environment. c. Expert construction planning/scheduling techniques

Effect of damping on excitability of high-order normal modes

The effect of localized structural damping on the excitability of higher-order large space telescope spacecraft modes is investigated. A preprocessor computer program is developed to incorporate Voigt structural joint damping models in a finite-element dynamic model. A postprocessor computer program is developed to select critical modes for low-frequency attitude control problems and for higher-frequency fine-stabilization problems. The selection is accomplished by ranking the flexible modes based on coefficients for rate gyro, position gyro, and optical sensor, and on image-plane motions due to sinusoidal or random PSD force and torque inputs

Estimating Wettability of Rock Fracture Surfaces from Contact Angle and Roughness Measurements

Estimates of wettability are important for modeling multi-phase flow and transport in the subsurface. This study investigates the wettability of rock fracture surfaces through contact angle measurements and surface roughness characterization. Droplet diameter and advancing contact angle were determined at 0.5s intervals for ~90s on flat polished disks of Burlington Limestone, Crossville Sandstone, Mancos Shale, Sierra White Granite, Vermilion Bay Granite (2 types), and Westerly Granite using a Krüss DSA 30 Drop Shape Analyzer. The droplet diameter and advancing contact angle data sets were nonlinearly regressed against time using two different two-parameter models. The resulting parameter estimates were used to compute the apparent equilibrium contact angle, θe, for each disk following droplet diameter stabilization. Estimates of θe ranged from 37.2° for Mancos Shale to 75.6° for Burlington Limestone. Analysis of variance indicated statistically significant differences in θe between the rock types at the 95% confidence level. Height maps for fractured surfaces of these rocks were made using a Phenom Pro X SEM and analyzed for Wenzel roughness factor and fractal dimension using multi-image variography. The Mancos Shale and Crossville Sandstone were found to be fractal, both having a mean fractal dimension of 2.16. The Wenzel roughness factor was found to increase with increasing length scale. Mean Wenzel roughness factors for the 200 to 600 μm fields were found to have significant differences between rock types. Using the Wenzel roughness factor and contact angle results in the Wenzel model, four of the rock types were found to have a rough surface contact angle of 0°, indicating complete wettability; the Burlington Limestone, Mancos Shale, and Westerly Granite had contact angles greater than zero but less than their contact angles for flat polished surfaces. This is, to the best of our knowledge, the first time the Wenzel model has been used to quantify rough surface contact angles for rocks. The transient analysis employed in this study also permits a more meaningful estimate of the equilibrium contact angle for polished rock surfaces, rather than taking the initial value or averaging over time as is frequently done

The effects of localized damping on structural response

The effect of localized structural damping on the excitability of higher order normal modes of the large space telescope was investigated. A preprocessor computer program was developed to incorporate Voigt structural joint damping models in a NASTRAN finite-element dynamic model. A postprocessor computer program was developed to select critical modes for low-frequency attitude control problems and for higher frequency fine-stabilization problems. The mode selection is accomplished by ranking the flexible modes based on coefficients for rate gyro, position gyro, and optical sensors, and on image-plane motions due to sinusoidal or random power spectral density force and torque inputs