Equilibrium properties of the Skylab CMG rotation law

The equilibrium properties of the control moment gyroscopes of the Skylab are discussed. A rotation law is developed to produce gimbal rates which distribute the angular momentum contributions among the control moment gyroscopes to avoid gimbal stop encounters. The implications for gimbal angle management under various angular momentum situations are described. Conditions were obtained for the existence of equilibria and corresponding stability properties

Diabetes Health Literacy in the Rural Community: An Integrative Review

Health literacy is paramount for successful management of health and prevention of disease. Yet a majority of adults have low health literacy. The impact of low health literacy on chronic disease management effects health outcomes and health care costs. With six out of 10 adults in the US diagnosed with a chronic disease such as diabetes, health literacy is a serious concern. Diabetes impacts over 30.3 million Americans. Since diabetes is one of the most common chronic diseases in the country, it is imperative that health literacy be addressed as part of this population’s health management. Diabetes health literacy plays a substantial role in disease management by increasing successful self-management behaviors. Rural populations in particular have lower levels of health literacy and higher incidence of diabetes, making this population at increased risk for morbidity and complications such as vision loss, cardiac disease and kidney failure. The geographical and demographic inequities of the rural population provide unique challenges that impact diabetes health literacy. Given the statistics related to diabetes and diabetes health literacy in the rural community, it is paramount that providers working in these communities acknowledge the factors that influence diabetes health literacy and are knowledgeable of interventions and strategies that impact diabetes health literacy. This integrative review examines the state of evidence regarding diabetes health literacy in the rural community in an effort to support health care providers in improving diabetes health literacy in this at-risk population

NASA follow-on to the Bangladesh Agro-Climatic Environmental Monitoring Project

The NASA responsibility and activities for the follow-on to the original Agro-Climatic Environmental Monitoring Project (ACEMP) which was completed during 1987 is described. Five training sessions which comprise the NASA ACEMP follow-on are: Agrometeorology, Meteorology of Severe Storms Using GEMPAK, Satellite Oceanography, Hydrology, and Meteorology with TOVS. The objective of the follow-on is to train Bangladesh Government staff in the use of satellite data for remote sensing applications. This activity also encourages the scientific connection between NASA/Goddard Space Flight Center and The Bangladesh Space and Remote Sensing Organization (SPARRSO)

ISM In-Space Manufacturing

Develop and enable the technologies, materials, and processes required to provide affordable, sustainable on-demand manufacturing, recycling, and repair during Exploration Missions

Tuning the Viscoelastic Properties of Hyaluronic Acid-Based Thiolene Hydrogels for Tissue Engineering Applications

AbstractOsteoarthritis (OA) affects 300 million people worldwide, with roughly 80% of these cases being knee OA. While there are many events that promote OA, injury and maladaptive repair of the meniscal discs is a major factor. Considerable prior research has examined mechanisms behind regenerating avascular meniscal tissue, however, many limitations in both in vivo and in vitro models exist. The literature demonstrates that hyaluronic acid (HA) has viscoelastic properties conducive to tissue regeneration and specifically the rate of stress relaxation creates a regenerative cellular response not yet examined in meniscal cells1. The linear HA polymer has limited mechanical properties; however, functionalization using adaptive chemical moieties to promote crosslinking has been previously used to optimize those properties for tissue engineering applications. Common examples include use as injectables and scaffolds which creates further potential for implementation as extracellular matrix (ECM) mimics for in vitro studies of cell behavior and differentiation. HA functionalized with increasing amounts of pentenoic acid (PHA) provided a thiol-ene “click” chemistry platform to promote chain growth polymerization, and optimize crosslink density to modulate hydrogel network properties, including swelling and compressive properties. Herein, the role of degree of -ene substitution, modulated by the HA monomer to pentenoic acid molar ratio, on crosslink density and resulting network properties was investigated in water, phosphate buffered saline, and human cell complete growth media. Crosslink density was shown modulate the mechanical and physical characteristics of the hydrogels including swelling, compression, viscoelasticity, uniform network formation and degradation. The increased crosslinking led to reduction in swelling, increase in compressive modulus, a shift in the viscoelastic properties and reduction in mesh size and rate of degradation. In PBS and complete growth media with increased ionic strength, osmotic deswelling resulted in reduced swelling and reduced compressive modulus values of the gels. PHA hydrogels showed considerable progress toward the goal of producing a tunable hydrogel that resembles the ECM physically and viscoelastically. The robust production delivered reproducible degree of substitution (DoS) as a function of input ratios. The limitations of the system were apparent as the DoS increased and the possible occurrence of intramolecular thiol-ene reactions were increasing. By performing experiments in ionic solutions to mimic physical conditions it was evident that the ionic contributions from the solutions decreased the range of outputs for the gels due to osmotic deswelling. Even with osmotic deswelling the system is robust and allows for the control of the viscoelastic components of these hydrogels. This control is fundamental for utilization of the PHA system in future stress-relaxation studies. Across all conditions, the viscoelastic properties followed trends shown in native soft tissues including meniscal tissue, which is of interest for future studies

First Evidence of Persistent Nighttime Temperature Structures in the Neutral Thermosphere of Mars

Using two Mars years of data collected by the Neutral Gas and Ion Mass Spectrometer on the Mars Atmosphere and Volatiles EvolutioN spacecraft, we reconstruct the local solar time structure of the Martian equatorial thermosphere for the dawn and dusk sectors. The results indicate the presence of several persistent features near the dusk and dawn terminators appearing in the neutral temperature and in the O, Ar, N2, and CO2 densities. The dusk temperature features include a minimum at the terminator surrounded by two local maxima with amplitudes between 20 and 40 K. A nighttime temperature enhancement occurs at a local solar time of 4–5 hr and has an amplitude between 50 and 100 K relative to the surrounding temperatures. The observed enhancements are interpreted to be a result of either nighttime dynamical heating caused by converging and downwelling winds or of a terminator wave originating in the lower atmosphere.Plain Language SummaryNASA’s Mars Atmosphere and Volatiles EvolutioN (MAVEN) spacecraft has been collecting information about the Mars’ upper atmosphere since November 2014. In our study we examined the temperature in the upper atmosphere measured by a gas analyzer on MAVEN that periodically sniffs the air around it. By combining several years of data, we reconstructed a map of atmospheric temperatures dividing it into equatorial daytime, morning, evening, and nighttime regions. The results indicate that local patches of warm atmosphere extend about 300–600 km along the Martian equator (3–6 hr driving distance at highway speeds) on the nightside near morning and evening. One possible reason for these nighttime warm spots is the air currents in the Martian upper atmosphere. As the sun heats the dayside atmosphere, it expands and causes wind currents to blow away from the dayside region. These wind currents can extend away from the equator then return on the nightside colliding in the morning and evening regions. The resulting meeting of wind currents can heat the upper atmosphere. Warmer air escapes from the upper atmosphere faster. Because of this, these nighttime patches of warm air could have contributed to a faster escape of Martian atmospheric gases than previously believed.Key PointsPersistent neutral density and temperature enhancements are observed within 30 min of the dusk terminatorA persistent neutral density enhancement is also observed prior to the dawn terminator at around 4–5 local timeThe neutral density features are observed in all species and appear to be associated with enhancements in neutral temperaturePeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146482/1/grl57932.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146482/2/grl57932_am.pd

Distributed knowledge coordination across virtual organization boundaries

Paper presented at The International Conference of Information Systems (ICIS), in Milwaukee, WI.This paper examines boundary-spanning knowledge-coordination in the definition of information systems by the e-Commerce systems group for a global service consultancy. We report on the findings of an eighteen-month field study to investigate distributed and virtual knowledge coordination across organizational boundaries. Our study reveals multiple ways in which knowledge is coordinated by means of a web of functional and domain-expert roles, distributed knowledge-resources, and imposed or negotiated procedures. We identify a “problemcoordination distance” that relates to the organizational-span of coordination and the type of problems to be resolved. We observe that different forms of group memory are used to manage boundary-spanning collaboration according to three degrees of problem-coordination-distance. These findings are related to the potential use of knowledge management systems to support boundary-spanning coordination for enterprise managers in virtual organizations