New Uses for Sensitivity Analysis: How Different Movement Tasks Effect Limb Model Parameter Sensitivity

Original results for a newly developed eight-order nonlinear limb antagonistic muscle model of elbow flexion and extension are presented. A wider variety of sensitivity analysis techniques are used and a systematic protocol is established that shows how the different methods can be used efficiently to complement one another for maximum insight into model sensitivity. It is explicitly shown how the sensitivity of output behaviors to model parameters is a function of the controller input sequence, i.e., of the movement task. When the task is changed (for instance, from an input sequence that results in the usual fast movement task to a slower movement that may also involve external loading, etc.) the set of parameters with high sensitivity will in general also change. Such task-specific use of sensitivity analysis techniques identifies the set of parameters most important for a given task, and even suggests task-specific model reduction possibilities

Fabrication of composite fan blades using PMR A-type polyimide resin and graphite fiber reinforcement

PMR polyimides are safe, easy to handle, can be processed with relatively wide process controls, and offer excellent mechanical properties, with thermo-oxidative stability. Procedures, staging and cure schedules fully dense, crackfree, dimensionally controlled, complex structure: high tip speed fan blades 1.27 cm (0.5 in) thick

Quantitation and organic geochemical characterization of petroleum-like materials found on an undisturbed beach of the Padre Island National Seashore

On June 3, 1979 the IXTOC I well in the Bay of Campeche 'blew out' with the subsequent release of 3 to 4 million barrels of oil. A major portion of that oil is known to have escaped recovery or was deliberately dispersed into the environment. This catastrophic source appears to be a major contributor to coastal water petroleum residues of the Gulf. Two questions which arise are: 1) What quantities of this petroleum-like material are being deposited annually on the south Texas beaches? And 2), is there a single source of beach tar (seeps) or are there multiple sources (spilled or dumped crudes as well as seeps)? This study is part of an effort to find answers to these questions.A report submitted to: United States Department of the Interior, National Park Service, Southwest RegionMarine Scienc

Affordable, Entropy Conserving and Entropy Stable Flux Functions for the Ideal MHD Equations

In this work, we design an entropy stable, finite volume approximation for the ideal magnetohydrodynamics (MHD) equations. The method is novel as we design an affordable analytical expression of the numerical interface flux function that discretely preserves the entropy of the system. To guarantee the discrete conservation of entropy requires the addition of a particular source term to the ideal MHD system. Exact entropy conserving schemes cannot dissipate energy at shocks, thus to compute accurate solutions to problems that may develop shocks, we determine a dissipation term to guarantee entropy stability for the numerical scheme. Numerical tests are performed to demonstrate the theoretical findings of entropy conservation and robustness.Comment: arXiv admin note: substantial text overlap with arXiv:1509.06902; text overlap with arXiv:1007.2606 by other author

Georgia's Immigrants: Past, Present, and Future

This report uses data from the most recent decennial censuses to analyze and assess the composition and experience ofimmigrants to Georgia, with special attention paid to the Atlanta metropolitan area, where the majority of the immigrants have settled. FRC Report 17

On the Formation of Multiple-Shells Around Asymptotic Giant Branch Stars

Two types of models for the formation of semi-periodic concentric multiple shells (M-shells) around asymptotic giant branch (AGB) stars and in planetary nebulae are compared against observations. Models that attribute the M-shells to processes in an extended wind acceleration zone around AGB stars result in an optically thick acceleration zone, which reduces the acceleration efficiency in outer parts of the extended acceleration zone. This makes such models an unlikely explanation for the formation of M-shells. Models which attribute the M-shell to semi-periodic variation in one or more stellar properties are most compatible with observations. The only stellar variation models on time scales of 50-1500 years that have been suggested are based on an assumed solar-like magnetic cycle. Although ad-hoc, the magnetic cycle assumption fits naturally into the increasingly popular view that magnetic activity plays a role in shaping the wind from upper AGB stars.Comment: 8 pages, Submitted to Ap

Year-end seasonality in one-month LIBOR derivatives

We examine the markets for one-month LIBOR futures contracts and options on those futures for a year-end price effect consistent with the previously identified year-end rate increase in one-month LIBOR. The cash market rate increase appears in forward rates and derivative prices, which allows the derivatives to properly hedge year-end interest rate risk. However, while the year-end effect appears in the derivative contract, these derivative contracts provide biased forecasts of both future interest rates and their volatility. The bias appears to be different at year's end for the LIBOR futures contract, but not for the options contract. The information in the derivatives almost always subsumes simple benchmark forecasts. ; Earlier title: Seasonality in one-month LIBOR derivativesEconometrics ; Monetary policy ; Finance

PMR polyimide/graphite fiber composite fan blades

Ultrahigh speed fan blades, designed in accordance with the requirements of an ultrahigh tip speed blade axial flow compressor, were fabricated from a high strength graphite fiber tow and a PMR polyimide resin. The PMR matrix was prepared by combining three monomeric reactants in methyl alcohol, and the solution was applied directly to the reinforcing fiber for subsequent in situ polymerization. Some of the molded blades were completely finished by secondary bonding of root pressure pads and an electroformed nickel leading edge sheath prior to final machining. The results of the spin testing of nine PMR fan blades are given. Prior to blade fabrication, heat resin tensile properties of the PMR resin were examined at four formulated molecular weight levels. Additionally, three formulated molecular weight levels were investigated in composite form with both a high modulus and a high strength fiber, both as-molded and postcured, in room temperature and 232 C transverse tensile, flexure and short beam shear. Mixed fiber orientation panels simulating potential blade constructions were also evaluated. Flexure tests, short beam shear tests, and tensile tests were conducted on these angle-plied laminates

Consistency Conditions for Brane Worlds in Arbitrary Dimensions

We consider ``brane world sum rules'' for compactifications involving an arbitrary number of spacetime dimensions. One of the most striking results derived from such consistency conditions is the necessity for negative tension branes to appear in five--dimensional scenarios. We show how this result is easily evaded for brane world models with more than five dimensions. As an example, we consider a novel realization of the Randall--Sundrum scenario in six dimensions involving only positive tension branes.Comment: 18 pages, LaTex, refs. adde

Model simulation studies to clarify the effect on saccadic eye movements of initial condition velocities set by the Vestibular Ocular Reflex (VOR)

Voluntary active head rotations produced vestibulo-ocular reflex eye movements (VOR) with the subject viewing a fixation target. When this target jumped, the size of the refixation saccades were a function of the ongoing initial velocity of the eye. Saccades made against the VOR were larger in magnitude. Simulation of a reciprocally innervated model eye movement provided results comparable to the experimental data. Most of the experimental effect appeared to be due to linear summation for saccades of 5 and 10 degree magnitude. For small saccades of 2.5 degrees, peripheral nonlinear interaction of state variables in the neuromuscular plant also played a role as proven by comparable behavior in the simulated model with known controller signals