Simulation validation and flight prediction of UH-60A Black Hawk helicopter/slung load characteristics

Helicopter/slung load systems are two body systems in which the slung load adds its rigid body dynamics, aerodynamics, and sling stretching dynamics to the helicopter. The slung load can degrade helicopter handling qualities and reduce the flight envelope of the helicopter. Confirmation of system stability parameters and envelope is desired, but flight test evaluation is time consuming and costly. A simulation model validated for handling quality assessments would significantly reduce resources expended in flight testing while increasing efficiency, productivity, and safety by aiding researchers, designers, and pilots to understand factors affecting helicopter-slung load handling qualities. This thesis describes a comprehensive dynamics and aerodynamics model for slung load simulation, obtained by integrating the NASA Ames Gen Hel UH-60A simulation with slung load equations of motion. Frequency domain analysis is used to compare simulation to flight test frequency responses and key system stability parameters. Results are given for no load, a 4K lb Block, and a 4K lb CONEX load. Handling quality parameters, stability margins, and load pendulum motion roots for cases without load aerodynamics and with static wind tunnel data were compared. Results illustrated state-of-the-art simulation modeling of helicopter/slung load dynamics and its accuracy in predicting key dynamic parameters of interest.http://archive.org/details/simulationvalida1094513648U.S. Navy (U.S.N.) author.Approved for public release; distribution is unlimited

Guiding chemical pulses through geometry: Y-junctions

We study computationally and experimentally the propagation of chemical pulses in complex geometries.The reaction of interest, CO oxidation, takes place on single crystal Pt(110) surfaces that are microlithographically patterned; they are also addressable through a focused laser beam, manipulated through galvanometer mirrors, capable of locally altering the crystal temperature and thus affecting pulse propagation. We focus on sudden changes in the domain shape (corners in a Y-junction geometry) that can affect the pulse dynamics; we also show how brief, localized temperature perturbations can be used to control reactive pulse propagation.The computational results are corroborated through experimental studies in which the pulses are visualized using Reflection Anisotropy Microscopy.Comment: submitted to Phys. Rev.

The Installation, Operation and Analysis of Eddy Covariance for Quantifying Evapotranspiration

During the contract period from January 2021 through December 31, 2023, the University of Texas at Austin, Bureau of Economic Geology (UT-BEG) installed and maintained two eddy covariance stations across the Edwards Aquifer recharge region. The Cibolo station was installed on February 25, 2021, in the more humid eastern portion of the region within an oak-ashe juniper ecosystem adjacent to Cibolo Creek at the Field Research Park (FRP) operated by the Edwards Aquifer Authority (EAA). The Uvalde station was installed on April 8, 2021, in the more arid western portion of the region within a mesquite woody savanna northwest of Uvalde, TX, near the Nueces River. The Uvalde station was demobilized on March 1, 2023, and relocated to a permanent location approximately 30 miles north, within an oak-ashe juniper woody savanna on the Shield Ranch east of Camp Wood, TX, and renamed the Nueces station. Installation of the Nueces station was completed on July 19, 2023. Site visits were performed throughout the contract period for regular maintenance, such as calibrating (i.e., zero-spanning) the infrared gas analyzer, and as-needed maintenance such as troubleshooting issues with power, communication or individual sensors. The Cibolo, Uvalde, and Nueces sites have been registered with AmeriFlux (a collaborative network of flux site across North, Central, and South America with standardized processes and procedures) with site designations of US-EA4, US-EA5, and US-EA6, respectively. Data submission to AmeriFlux for the eddy covariance sites is ongoing.Bureau of Economic Geolog

Spin-Coupled Local Distortions in Multiferroic Hexagonal HoMnO3

Local structural measurements have been performed on hexagonal HoMnO3 in order to ascertain the specific changes in bond distances which accompany magnetic ordering transitions. The transition from paramagnetic to the antiferromagetic (noncollinear) phase near ~70 K is dominated by changes in the a-b plane Mn-Mn bond distances. The spin rotation transition near ~40 K involves both Mn-Mn and nearest neighbor Ho-Mn interactions while the low temperature transition below 10 K involves all interactions, Mn-Mn, Ho-Mn (nearest and next nearest) and Ho-Ho correlations. These changes in bond distances reveal strong spin-lattice coupling. The similarity in magnitude of the change in J(Mn-Mn) and J(Ho-Mn) enhances the system frustration. The structural changes are interpreted in terms of a model of competing spin order and local structural distortions. Density functional calculations are used to estimate the energies associated with ionic displacements. The calculations also reveal asymmetric polarization of the charge density of Ho, O3 and O4 sites along the z-axis in the ferroelectric phase. This polarization facilitates coupling between Ho atoms on neighboring planes normal to the z-axis.Comment: 8 figure

Psychosocial Mechanisms Underlying Older Black Men’s Health

Objectives: To evaluate the psychosocial mechanisms underlying older Black men's self-rated health, we examined: (a) the individual, cumulative, and collective effects of stressors on health; (b) the direct effects of psychosocial resources on health; and (c) the stress-moderating effects of psychosocial resources. Method: This study is based on a nationally representative sample of Black men aged 51-81 (N = 593) in the Health and Retirement Study (HRS). Ordinary least squares (OLS) regression models of the psychosocial determinants of self-rated health draw on data from the HRS 2010 and 2012 Core datasets and Psychosocial Modules. Results: Each of the six measures of stressors as well as a cumulative measure of stressors are predictive of worse self-rated health. However, when considered collectively, only two stressors (chronic strains and traumatic events) have statistically significant effects. Furthermore, two of the five psychosocial resources examined (mastery and optimism) have statistically significant protective effects, and prayer moderates the harmful effects of traumatic events on self-rated health. Discussion: Conventional measures of stressors and coping resources-originally developed to account for variance in health outcomes among predominantly white samples-may not capture psychosocial factors most salient for older Black men's health. Future research should incorporate psychosocial measures that reflect their unique experiences

Flow Injection Atomic Absorption Spectrometry: The Kinetics of Instrument Response

The concept of dispersion coefficient is discussed with particular reference to flow injection atomic absorption spectrometry where the detector contributes appreciably to the analytical signal characteristics. Single- and parallel-tank models of instrument response are developed and critically examined. The progress made to date by investigators of nebuliser performance is briefly reviewed prior to developing a semi-empirical extended-tank model of instrument response. The capabilities of this model are explored by deriving a set of equations for instrument response, and comparing the predictions with experimental results. Agreement is generally good. Advantages of the modelling approach are discussed

My True Heart In Days Of Old

https://digitalcommons.library.umaine.edu/mmb-vp/2246/thumbnail.jp

Preliminary Characterization of Peroxidase Isozymes Isolated from Two Flax Genotrophs

Four peroxidase (EC 1.11.1.7) isozymes were isolated from each of two flax genotrophs. All four isozymes were glycoproteins and all exhibited indoleacetic acid (IAA) oxidase activity. The percentage purity of two of the isozymes was very high; these isozymes differed in percentage carbohydrate and in peroxidase and IAA oxidase specific activities. Three of the isozymes displayed molecular weight values of about 43 000; for the fourth, molecular weight was considerably higher. Corresponding isozymes from the genotrophs and from two other flax genotypes displayed molecular weight differences which corresponded to electrophoretic relative mobility differences. Enzyme yield per unit fresh weight was higher for one genotroph than the other, and the balance between peroxidase activity and IAA oxidase activity between the genotrophs was different

Pressure effects on charge, spin, and metal-insulator transitions in narrow bandwidth manganite Pr1−x_{1-x}Cax_{x}MnO3_{3}

Pressure effects on the charge and spin states and the relation between the ferromagnetic and metallic states were explored on the small bandwidth manganite Pr$_{1-x}$Ca$_{x}$MnO$_{3}$ (x = 0.25, 0.3, 0.35). Under pressure, the charge ordering state is suppressed and a ferromagnetic metallic state is induced in all three samples. The metal-insulator transition temperature (T$_{MI}$) increases with pressure below a critical point P*, above which T$_{MI}$ decreases and the material becomes insulating as at the ambient pressure. The e$_{g}$ electron bandwidth and/or band-filling mediate the pressure effects on the metal-insulator transition and the magnetic transition. In the small bandwidth and low doping concentration compound (x = 0.25), the T$_{MI}$ and Curie temperature (T$_{C}$) change with pressure in a reverse way and do not couple under pressure. In the x = 0.3 compound, the relation of T$_{MI}$ and T$_{C}$ shows a critical behavior: They are coupled in the range of $\sim$0.8-5 GPa and decoupled outside of this range. In the x = 0.35 compound, T$_{MI}$ and T$_{C}$ are coupled in the measured pressure range where a ferromagnetic state is present