X-ray Amorphous Components of Antarctica Dry Valley Soils: Weathering Implications for Mars

The Antarctic Dry Valleys (ADV) comprise the largest ice-free region of Antarctica. Precipitation usually occurs as snow, relative humidity is frequently low, and mean annual temperatures are about -20C [1]. Substantial work has focused on soil formation in the ADVs [2], however, little work has focused on the mineralogy of secondary alteration phases. The dominant weathering process in the ADV region is physical weathering, however, chemical weathering has been well documented [3]. The occurrence of chemical weathering processes are suggested by the presence of clay minerals and iron and titanium oxides in soil. Previously we have investigated soils from two sites in the ADVs and have shown evidence of chemical weathering by the presence of clay minerals (vermiculite, smectite), short-range ordered (SRO) and/or X-ray amorphous materials, and Fe- and Tioxides as well as the presence of discrete calcite crystals [4, 5]. The Chemistry and Mineralogy (CheMin) instrument onboard the Mars Curiosity rover has detected abundant amounts (approx. 25-30 wt. %) of X-ray amorphous materials in a windblown deposit or soil (Rocknest) and in a sedimentary rocks [6,7,8]. The occurrence of large amounts of X-ray amorphous materials in Mars sediments is surprising because these materials are usually present in small quantities in terrestrial environments. The objective of this study is to further characterize the chemistry and mineralogy, specifically the secondary alteration mineralogy and the presence of X-ray amorphous material, of soils from two sites we have previously studied, a subxerous soil in Taylor Valley, and an ultraxerous soil in University Valley. While the chemical alteration processes and mineralogy of the ADV has been documented previously, there has been limited discussion on the occurrence and formation of X-ray amorphous and SRO materials in Antarctica soils. The process of aqueous alteration in the ADVs may have implications for pedogenic processes on Mars, and may lead to a better understanding to the abundance of amorphous material found in sediments in Gale crater

Power systems research at MSFC

Power systems research reviews at Marshall Space Flight Cente

Electrochemical Energy Storage Subsystems Study, Volume 2

The effects on life cycle costs (LCC) of major design and performance technology parameters for multi kW LEO and GEO energy storage subsystems using NiCd and NiH2 batteries and fuel cell/electrolysis cell devices were examined. Design, performance and LCC dynamic models are developed based on mission and system/subsystem requirements and existing or derived physical and cost data relationships. The models are exercised to define baseline designs and costs. Then the major design and performance parameters are each varied to determine their influence on LCC around the baseline values

Electrochemical energy storage subsystems study, volume 1

The effects on life cycle costs (LCC) of major design and performance technology parameters for multi kW LEO and GEO energy storage subsystems using NiCd and NiH2 batteries and fuel cell/electrolysis cell devices were examined. Design, performance and LCC dynamic models are developed based on mission and system/subsystem requirements and existing or derived physical and cost data relationships. The models define baseline designs and costs. The major design and performance parameters are each varied to determine their influence on LCC around the baseline values

Coherent phonon scattering effects on thermal transport in thin semiconductor nanowires

The thermal conductance by phonons of a quasi-one-dimensional solid with isotope or defect scattering is studied using the Landauer formalism for thermal transport. The conductance shows a crossover from localized to Ohmic behavior, just as for electrons, but the nature of this crossover is modified by delocalization of phonons at low frequency. A scalable numerical transfer-matrix technique is developed and applied to model quasi-one-dimensional systems in order to confirm simple analytic predictions. We argue that existing thermal conductivity data on semiconductor nanowires, showing an unexpected linear dependence, can be understood through a model that combines incoherent surface scattering for short-wavelength phonons with nearly ballistic long-wavelength phonons. It is also found that even when strong phonon localization effects would be observed if defects are distributed throughout the wire, localization effects are much weaker when defects are localized at the boundary, as in current experiments.Comment: 13 page

Solar power satellite: Analysis of alternatives for transporting material to geosynchronous orbit

A systems design study of the alternative methods and relative merits of various approaches to transporting and assembling a solar power satellite in geosynchronous orbit was conducted. State of the art alternatives for chemical and electrical interorbital propulsion were studied, and several possible scenarios for construction were proposed

Survey of Colorado Tick Fever Virus Presence in Montana Deer Mice and Wood Ticks

Colorado Tick Fever Virus (CTFV) is carried by Rocky Mountain wood ticks (Demacetori andersoni). Its double-stranded RNA genome is comprised of twelve segments. In humans, it causes a variety of flu-like symptoms, including fever, headache, sensitivity to light, and muscle soreness. Because the symptoms often mimic the flu and other common diseases, it is often overlooked during clinical diagnosis. Deer mice (Peromyscus manisculatus) are considered to be a reservoir for the virus. This study aimed to determine the prevalence of CTFV nucleic acid in mouse blood. The whole blood samples were screened from Polson and Gregson, Montana. These samples were collected both prior to the study for a separate Hantavirus study as well as during the study. Only Hantavirus negative samples were screened. In addition, ninety ticks were collected. While these have not been tested, they provide another sample set to screen for the presence of CTFV.https://digitalcommons.mtech.edu/urp_aug_2017/1001/thumbnail.jp

Evaluating the Function of an Understudied Family of Antiviral Proteins

Human immune responses to viral infections are associated with the interferon system, which induces the expression of as many as 300 proteins. Many of these proteins are believed to have antiviral functions, yet many of the interferon stimulated genes (ISGs) remain poorly characterized. The goal of this research is to identify the functional role of ISGs that are members of the tripartite motif (TRIM) family of proteins. Here, we report the progress of TRIM gene cloning into plasmids used in the yeast two-hybrid assays. We hypothesize that protein-protein interactions identified in these assays will provide unbiased insights into the functional role of these putative antiviral proteins. The yeast-two hybrid assay is the cornerstone for a research pipeline designed to more fully characterize the TRIM proteins.https://digitalcommons.mtech.edu/urp_aug_2017/1002/thumbnail.jp

Flexor digitorum brevis tendon transfer to the flexor digitorum longus tendon according to Valtin in posttraumatic flexible claw toe deformity due to extrinsic toe flexor shortening

AbstractClaw toe deformity after posterior leg compartment syndrome is rare but incapacitating. When the mechanism is flexor digitorum longus (FDL) shortening due to ischemic contracture of the muscle after posterior leg syndrome, a good treatment option is the Valtin procedure in which the flexor digitorum brevis (FDB) is transferred to the FDL after FDL tenotomy. The Valtin procedure reduces the deformity by lengthening and reactivating the FDL. Here, we report the outcomes of FDB to FDL transfer according to Valtin in 10 patients with posttraumatic claw toe deformity treated a mean of 34 months after the injury. Toe flexion was restored in all 10 patients, with no claw toe deformity even during dorsiflexion of the ankle