Showing papers by "University of Colorado Colorado Springs published in 1971"

Apparatus for shearing rigid wall tubes

Abstract: A method and apparatus for shearing or breaking a metal tube or the like by confining and supporting the tube on both its inner and outer surfaces and on either side of a given shear plane, and then applying a shear force to the supported tube sufficient to break it transversely along the shear plane.

Microzone electrophoresis of unconcentrated cerebrospinal fluid using cellulose acetate strips and nigrosin dye.

Abstract: A unique method of microzone electrophoresis of cerebrospinal fluid protein using cellulose acetate strips, nigrosin dye, and less than 0.50 μ l. of unconcentrated cerebrospinal fluid is easily performed, and the results are superior to those of methods using conconcentrating technics. Albumin and globulin bind nigrosin dye equally, and the bound dye follows Beer’s law up to a concentration of 80 mg. per 100 ml. protein. Precision and accuracy are similar to those of serum protein electrophoresis. Two striking advantages of this method are that it is unnecessary to concentrate the spinal fluid, thereby eliminating protein denaturation and a tan fraction, and that only a minute quantity is needed for electrophoresis. Specimens from 300 consecutive patients having spinal fluid studies were evaluated by this technic. Abnormal electrophoretic patterns were found in patients with multiple sclerosis, peripheral neuropathy, Guillain-Barre syndrome, hydrocephalus, central nervous system neoplasms, and herniated intervertebral disks. Electophoretic study of the spinal fluid proved helpful in establishing a diagnosis.

Downflow Bubble Contact Aeration

Abstract: A simple system has been developed to efficiently absorb commercial oxygen and air into water. It consists of passing water down through a submerged cone-shaped hood. Oxygen or air is injected into the hood. The water velocity entering the smaller, top end of the hood is greater than the buoyant velocity of the bubbles. The water velocity leaving the larger, open bottom is less than the buoyant velocity of the bubbles. Thus, the bubbles are trapped inside the hood for efficient absorption. Oxygen absorption in excess of 90% was achieved with very low power input. The system has potential application in activated sludge, river reaeration, fish hatcheries, yeast production and hypolimnion aeration.

Test signals for music reproduction systems

Abstract: Experiments with both long, continuous tones and short, transient tones have shown that the human ear is insensitive to relative phase differences between fundamentals and overtones. Short notes from a piano and from a drum are studied here to show that the phase requirement for music reproduction is that the group velocity of the system be constant in the relatively narrow regions surrounding the fundamentals and overtones. The phase velocity across the audio spectrum does not have to be constant, thus easing the requirements on loudspeakers, crossover networks, and tape recorders. Pulse-testing schemes require minimum-phase behavior of a system for simple interpretation and therefore tend to overtest a music reproduction system. Random noise can be used as a test signal if elaborate processing equipment is available. However, the sinusoid is still the best test signal for determining distortion and relating device performance to theory.

A Factor Analysis of Winds to 60 km over Battery MacKenzie, C.Z.

Abstract: Factor-analysis techniques are used to estimate the residual variances of the wind components over Battery MacKenzie, C.Z. These residual variances represent the combination of small-scale effects and observation errors of the wind components at the levels concerned. The number of significant proper functions required to represent the wind sounding are estimated using the methods of factor analysis rather than relying on an arbitrary choice of some fraction of the total variance to determine the appropriate number. In making a persistence estimate of the wind components, only a very few of the significant proper functions are useful.

Gastric ulcer: clinical observations on cure rate, relapse rate, and possible malignant change

Abstract: 1) Cure rate Cure rate of gastric ulcers of the in-patient group are distinctly better than the out-patient group. And cure rates are related to the diameter and to the depth of the crater. 2) Relapse rate The relapse rate is highest in the group subjected to the longest periods of follow-up observation. More than 50% of relapsed gastric ulcer group were relapsed within one year and nearly 75% within two years. Relapses occured most commonly in the third, forth and fifth decades, less commonly in the older and younger age groups. And there is no statistical significance in the relationship between the sex, size, depth or location of the initial ulcer and relapse rate. From histological studies of stomachs resected because of relapse, it was noted that the relapsed ulcers occured very close to or at the actual edge of the previous healed ulcer. Relapses occured more frequently in that group which healed their ulcers in a longer time period than the group in a shorter time period. It is to be noted that smoking, irregular mealtime, physical and mental overwork, sleeplessness and general dietary habits were statiscally significant as tiological factors in gastric ulcer relapse. And more than one out of the above six important etiological factors were present coincidentally in a larger number of the relapsed ulcer cases. Relased ulcer take longer to heal than required for the healing of the initial ulcer. 3) Malignant changes From our follow-up study on 991 cases of healed gastric ulcers, only 4 cases may have changed from benignity to malignancy. We believe that it is safe to say that the rate of malignant change is extremely low in a ten year follow-up study.

Analysis of a pneumatic isolation system for inertial instrument testing

Abstract: : The dynamic behavior of the pneumatically-suspended isolation platform at the USAF Guidance and Control Laboratory was investigated. A computer simulation model was used to evaluate the effect of changing physical parameters of the pad suspension system, and to determine the requirements for improving the present configuration. Results of this study provided the motivation for incorporating an adjustable two-way flow valve between the upper and lower air chambers. This allowed setting the damping factor at a point which would optimize pad response, so as to minimize the peak amplification of the pad transfer function. (Author)

Nonlinear vortex interactions on wing-canard configurations

Abstract: : Close-coupled wing-canard configurations are ideally suited to applications in which high aircraft maneuverability is required at moderate speeds. The SAAB Viggen has exploited the advantages of placing canard and wing close together, but no theory has been capable of predicting the aerodynamics of this aircraft. In this investigation Sacks' method of simulating vortex sheets with distributions of discrete vortices has been applied to the study of the interaction of a slender wing with a nearly canard surface. The canard is detrimental to both lift and static longitudinal stability. The extent of canard wake roll-up is important in the interaction, and the flatter the wake the more adverse is the interaction. Downward canard deflection may lead to increases in lift of the entire configuration, and it is observed that for small vertical separations between the surfaces the forward portion of the wing is ineffective in producing lift. It is demonstrated that the canard can directly affect the pressure distribution on the wing and application of this configuration to direct lift control and control configured aircraft are noted. (Author)