Application of a computerized vibroacoustic data bank for random vibration criteria development

A computerized data bank system was developed for utilization of large amounts of vibration and acoustic data to formulate component random vibration design and test criteria. This system consists of a computer, graphics tablets, and a dry silver hard copier which are all desk top type hardware and occupy minimal space. Currently, the data bank contains data from the Saturn 5 and Titan 3 flight and static test programs. The vibration and acoustic data are stored in the form of power spectral density and one third octave band plots over the frequency range from 20 to 2000 Hz. The data were stored by digitizing each spectral plot by tracing with the graphics tablet. The digitized data were statistically analyzed, and the resulting 97.5 percent confidence levels were stored on tape along with the appropriate structural parameters. Standard extrapolation procedures were programmed for prediction of component random vibration test criteria for new launch vehicle and payload configurations. A user's manual is included to guide potential users through the programs

Metabolic response of environmentally isolated microorganisms to industrial effluents: Use of a newly described cell culture assay

An environmental application using a microtiter culture assay to measure the metabolic sensitivity of microorganisms to petrochemical effluents will be tested. The Biomedical Operations and Research Branch at NASA JSC has recently developed a rapid and nondestructive method to measure cell growth and metabolism. Using a colorimetric procedure the uniquely modified assay allows the metabolic kinetics of prokaryotic and eukaryotic cells to be measured. Use of such an assay if adapted for the routine monitoring of waste products, process effluents, and environmentally hazardous substances may prove to be invaluable to the industrial community. The microtiter method as described will be tested using microorganisms isolated from the Galveston Bay aquatic habitat. The microbial isolates will be identified prior to testing using the automated systems available at JSC. Sodium dodecyl sulfate (SDS), cadmium, and lead will provide control toxic chemicals. The toxicity of industrial effluent from two industrial sites will be tested. An effort will be made to test the efficacy of this assay for measuring toxicity in a mixed culture community

Evaluation of Fungal Metabolic Compounds Released to the Air in a Restricted Environment

The metabolic action of selected fungi species on common components of the interior of Space Station Freedom (SSF) will be tested. When present, volatile organic chemicals will be collected on porous polymer adsorbent columns. Using thermal desorption, the volatile compounds will be passed onto a gas chromatographic column for analysis. The Space Station Freedom (SSF) modular complex will largely be individually self contained and the established air environment will not be easily adjusted. The development and maintenance of a safe working environment offers a considerable challenge. Present plans for use of SSF acknowledge periods of manned activities and alternate times when the station is unmanned. The obvious necessity for clean and safe air and water during periods of use have been pursued as fundamental systems to SSF success. Somewhat less obvious, although perhaps of no less importance to the success of long term cyclic usage, are those periods of inactivity. It is during these periods when spores from microorganisms may be afforded the best conditions to germinate and in the vegetative form react with the complex synthetic chemical polymers which compose the furnishings and hardware of SSF nodes. Biodegradation could constitute a real hygiene problem, if the organisms form and release volatile organic chemicals. Similar problems have been documented in closed and improperly ventilated buildings and work spaces. Many of the metabolic products of fungi and bacterial growth create a variety of health problems. Analytical chemical techniques will first be used to document the growth of Aspergillus, Penicillium, and Cladosporium fungal species on the potential substrates Nomex and Kevlar. Any volatile organics that are released will be measured using the spectrum of gas adsorption chromatography. The level of microbial contamination that is necessary to produce such volatile compounds and the relative amounts expected to accumulate will be estimated

Optimization of payload mass placement in a dual keel space station

In order to keep a Space Station in a stable low-Earth orbit, angular momentum storage and translational attitude control systems will have to be used. In order to minimize the size of these attitude control systems, the induced gravity gradient torque effects will have to be minimized. This can be done by minimizing the cross-products of inertia of the Station through the management of payload placement with the Station geometry. A derived and automated methodology is presented which utilizes mathematical nonlinear programming techniques. An optimal arrangement of a set of five payloads on a Dual Keel Space Station was found that minimized the cross products of inertia and thus the required controllability resources

Interactive analysis of a large aperture Earth observations satellite

A system level design and analysis has been conducted on an Earth Observation Satellite (EOS) system using the Interactive Design and Evaluation of Advanced Spacecraft (IDEAS) computer-aided design and analysis program. The IDEAS program consists of about 40 user-friendly technical modules and an interactive graphics display. The reflector support system and feed mast of the EOS spacecraft are constructed with box-truss structural concept, a lattice configuration which can be packaged for delivery in a single Shuttle flight and deployed in orbit. The deployed spacecraft consists of a 120-m by 60-m parabolic focal axis. The spacecraft was modeled for structural, thermal, and control systems analysis and structural elements were designed. On-orbit dynamic and thermal loading analyses were conducted; spacecraft weights and developmental and first unit costs were determined

Benefits from synergies and advanced technologies for an advanced-technology space station

A configuration for a second-generation advanced technology space station has been defined in a series of NASA-sponsored studies. Definitions of subsystems specifically addressed opportunities for beneficial synergistic interactions and those potential synergies and their benefits are identified. One of the more significant synergistic benefits involves the multi-function utilization of water within a large system that generates artificial gravity by rotation. In such a system, water not only provides the necessary crew life support, but also serves as counterrotator mass, as moveable ballast, and as a source for propellant gases. Additionally, the synergistic effects between advanced technology materials, operation at reduced artificial gravity, and lower cabin atmospheric pressure levels show beneficial interactions that can be quantified in terms of reduced mass to orbit

Estimation in discretely observed diffusions killed at a threshold

Parameter estimation in diffusion processes from discrete observations up to a first-hitting time is clearly of practical relevance, but does not seem to have been studied so far. In neuroscience, many models for the membrane potential evolution involve the presence of an upper threshold. Data are modeled as discretely observed diffusions which are killed when the threshold is reached. Statistical inference is often based on the misspecified likelihood ignoring the presence of the threshold causing severe bias, e.g. the bias incurred in the drift parameters of the Ornstein-Uhlenbeck model for biological relevant parameters can be up to 25-100%. We calculate or approximate the likelihood function of the killed process. When estimating from a single trajectory, considerable bias may still be present, and the distribution of the estimates can be heavily skewed and with a huge variance. Parametric bootstrap is effective in correcting the bias. Standard asymptotic results do not apply, but consistency and asymptotic normality may be recovered when multiple trajectories are observed, if the mean first-passage time through the threshold is finite. Numerical examples illustrate the results and an experimental data set of intracellular recordings of the membrane potential of a motoneuron is analyzed.Comment: 29 pages, 5 figure

Time Series Analysis: A New Look at Some Old Problems

This dissertation gives a comprehensive report of my doctoral research in time series analysis from summer 2006 to spring 2009. It is comprised of two main efforts: interval estimation for an autoregressive parameter and arc length tests for equivalent ARIMA dynamics. Such problems are traditional in statistics, but three new theorems and several simulations are presented here that help elucidate new ways to handle them

Handshakes and Heartaches: Who Owns the Oil After Rogers v. Ricane

The Supreme Court of Texas recently denied rehearing Rogers v. Ricane Enterprises, Inc., thereby reaffirming their restriction of the Davis doctrine, a 70-year-old principle that allowed a mineral lease to terminate when the operator completely abandoned the purpose of the mineral lease. Although the Davis doctrine itself is a narrow rule of Texas oil and gas law, and rarely applied today, the questions raised in Rogers v. Ricane expose the tenuous foundation of oil and gas law built in large measure on handshake deals3 and good will. The law of oil and gas is based on the uncomfortable marriage of contract and property law. Rogers v. Ricane illustrates the confusion that can arise when a court applies these principles. This comment examines the difficulty Texas courts have intrepreting oil and gas partial assignments, which they may do by looking at the writing itself against the backdrop of common industry practice. First, the article reviews Texas law in this area and then looks at the Rogers v. Ricane Enterprises, Inc. decisions

A Golf Fitness Program to Develop Clinical Skills in Student Physical Therapists: A Program Proposal, Development and Recommendations for Implementation.

PROBLEM: Golf is a fast-growing sport that is played by people all around the world of all ages and skill levels. The complexity of the golf swing and varying skill levels of participants leads to increased risk for injury. Acute and chronic musculoskeletal injuries can occur to the lumbar spine, shoulders, wrists, and elbows. The injuries are common among amateur, intermediate, and professional golfers. Studies show that the overall rate of injury in golfers is 15-20%. This is a surprisingly high amount of injuries for a low-impact sport. Physical therapists are an important healthcare provider for individuals with musculoskeletal injuries. The educational curriculum for physical therapists provides opportunities to perform various examination and treatment skills although much of this practice is performed on classmates with negligible musculoskeletal limitations. A golf fitness program performed by physical therapist students under the direction of a licensed physical therapist could minimize the risk of musculoskeletal injuries to golfers with evaluation of golfing movements and general fitness recommendations. Therefore, a golf fitness program could provide a needed community service and help develop the examination and communication skills of future physical therapists. PROCEDURE/METHODS: A review of multiple research databases (DynaMed, MD Consult, InfoPOEMS, PubMed, CINAHL, etc.) was used to identify current literature related to optimal golf swing mechanics and common golf related musculoskeletal injuries. Physical therapy and exercise science literature was obtained to identify musculoskeletal limitations in range of motion and strength that are commonly linked to golf-related injuries. The golf injury information and optimal swing mechanics were developed into a comprehensive pre-golf musculoskeletal screening process. The screening process was presented to a small group of young adult golfers for feedback and recommendations. The small group feedback was incorporated to develop a final pre-golf evaluation form and process that can be used by the UND Department of Physical Therapy as a community service activity for first- or second-year students in the professional DPT program. RESULTS: The final product is a comprehensive, pre-golf fitness and swing evaluation program. The program may be implemented in the spring semester when golfers are preparing for the upcoming summer season. The popularity of golf and high number of golf related injuries should drive interest in the program. The benefits to the current DPT students and local golfing community are symbiotic. Physical therapist students participating in the program may use this opportunity to enhance their evaluation and communication skills while golfers benefit from the comprehensive golf assessment program