Characterization of ionic liquid monopropellants for a multi-mode propulsion system

Multi-mode micropropulsion is a potential game-changing technology enabling rapidly composable small satellites with unprecedented mission flexibility. Maximum mission flexibility requires one shared propellant between the chemical and electric systems. A deep eutectic 1:2 molar ratio mixture of choline-nitrate and glycerol ([Cho][NO3] - glycerol) is investigated as a fuel component in a binary mixture propellant for such a multi-mode micropropulsion. Specifically, binary mixtures of the novel ionic liquid fuel with hydroxyl-ammonium nitrate (HAN) and ammonium nitrate (AN) are considered and compared against the previously investigated propellant [Emim][EtSO4]-HAN. Chemical rocket performance simulations predict this new propellant to have higher performance at lower combustion temperature, relaxing catalyst melting temperature requirements and making it a promising alternative. A qualitative investigation of synthesized propellants on a hot plate in atmosphere indicates the AN mixtures are significantly less reactive, and are therefore not investigated further. Quantitative reactivity studies using a microreactor indicate both 65:35% and 80:20% by mass [Cho][NO3] - glycerol to HAN propellants have a decomposition temperature 26-88% higher than [Emim][EtSO4]-HAN, depending on the catalyst material. The results indicate [Emim][EtSO4]-HAN with platinum catalyst is still most promising as a multi-mode micropropulsion propellant. Also, the linear burn rate of this monopropellant is determined to aid design of the microtube catalytic chemical thruster. With the design pressure of 1.5 MPa the linear burn rate of this propellant used for designing the multi-mode propulsion system is 26.4 mm/s. Based on this result, the minimum flow rate required is 0.31 mg/s for a 0.1 mm inner diameter feed tube and 3180 mg/s for a 10 mm inner diameter feed tube --Abstract, page iv

Notes: Oriental Bittersweet in Grasslands Near Eastern Bluebird Nest Boxes

Oriental bittersweet (Celastrus orbiculatus Thunb.; hereafter OB) is an invasive, woody vine that has been expanding its range westward in North America since its introduction from East Asia in the mid-1700s for horticultural purposes (Albright et al. 2009, United States Department of Agriculture [USDA] 2012). Although typically a woodland problem in the United States (McNab and Meeker 1987), OB can invade grassland habitats (Fike and Niering 1999), likely sprouting from seeds dropped by birds and mammals (McNab and Meeker 1987, Greenberg et al. 2001, Sarver et al. 2008) and often developing into large, shrub-like tangles of intertwining stems (Fike and Niering 1999). Once established, OB can easily out-compete native plants because of its superior growth rate, high seed production, and high rates of seed dispersal and germination (Greenberg et al. 2001, Leicht and Silander 2006, Leicht-Young et al. 2007a, b). Oriental bittersweet was first reported in Minnesota in 2010, although it likely was present previous to that date (Minnesota Department of Agriculture [MDA] 2012, USDA 2012). Oriental bittersweet occurs mainly along highway corridors and has converted the forest-grassland edge habitat into OB monoculture jungles, overrunning and killing shrubs and trees. In many areas in southeastern Minnesota, OB has invaded deeper into grasslands along fence lines and around isolated shrubs and artificial nest boxes placed for eastern bluebirds (Sialia sialis; N. D. Mundahl, Winona State University, unpublished data)

05. Bird Communities Within a Prairie/Wetland Complex: Restoration of Former Wastewater Treatment Ponds in Southeastern Minnesota

Our 12-mo study examined the bird communities associated with three habitat types at differing stages of restoration within a prairie/wetland complex in southeastern Minnesota. The 25-ha site previously consisted of three municipal wastewater treatment ponds that were taken off-line in 2002. One pond was retained as a shallow wetland; the others were reconfigured and restored by planting with prairie vegetation (one pond in 2003 and the other pond in 2013) to provide habitat for both wetland and grassland birds. Timed walking surveys of birds in each habitat were made monthly from June 2014 through May 2015. We observed 48 bird species at the study site during the year, with red-winged blackbird, song sparrow, American tree sparrow, dickcissel, and American goldfinch accounting for 83% of total individuals. Bird abundance varied seasonally in all habitats (0–22 birds/min), peaking in April in prairies and in September in the wetland. The wetland held more bird species (39) than either old (22) or new (24) prairies, but prairies had much higher Simpson diversity (0.799–0.809) than the wetland (0.428). Bird communities of old and new prairies were more similar to each other (Bray–Curtis similarity¼0.517) than either was to the wetland community (0.297, 0.301). Bobolink, dickcissel, sedge wren, western meadowlark, and ring-necked pheasant were found in both old and new prairies, but these species were significantly more abundant (2.7 times more individuals) in the old prairie. Management of this site (plantings, control of invasives, prescribed burns) for improved bird diversity is continuing

10. Browsing by White-Tailed Deer on Invasive Oriental Bittersweet Spreading into Restored Grasslands

Non-native oriental bittersweet (Celastrus orbiculatus Thunb.) was first detected in southeastern Minnesota in 2010 and has spread from woodlands into adjacent grasslands. Anecdotal evidence suggests that browsing by white-tailed deer (Odocoileus virginianus) on young oriental bittersweet slows the growth and spread of this plant. This study assessed the population characteristics of density, age structure, growth rate, and branching morphology of oriental bittersweet in small, restored grasslands (mixed native grasses and forbs) in Winona County, Minnesota, and quantified the browsing damage inflicted by white-tailed deer on bittersweet and native red osier dogwood (Cornus sericea) at the end of winter. Bittersweet densities averaged 20 plants/m2 in grasslands near infested woodlands. Plants ranged in age from 1 to 7 yr, and growth rates (stem length) in plants greater than or equal to 2 yr old averaged only 9 cm/yr but were highly variable. Spread of bittersweet into grasslands from woodland edges averaged 48 m across all transects, but densities declined with increasing distance from woodlands. Winter browsing damage was present on 100% of all bittersweet and dogwood plants, with terminal buds removed from 70% (2,183 of 3,118) of all bittersweet branches and 99% (391 of 392) of all dogwood branches. Browsing seems to have suppressed fruiting in greater than or equal to 35% of plants greater than or equal to 2 yr old in the grasslands examined. Overwinter browsing by deer heavily damaged terminal buds and greatly reduced the growth rates of oriental bittersweet in restored grasslands in southeastern Minnesota, but not enough to prevent most plants in the population from maturing and producing fruit and seed

Stream Fishes Estimate Water Quality in Dayton-Montgomery County Park District Reserves

Author Institution: Department of Zoology, Miami University-MiddletownInformation on fish communities within seven streams and rivers in or near Dayton-Montgomery County Park District reserves was collected and analyzed to compile a preliminary species list for Park District waters and to estimate water quality of the streams. Fifty-two species of fishes were found in lotic habitats in or near the reserves, and more extensive sampling likely will reveal the presence of additional species. Index of Biotic Integrity (IBI) scoring of the fish communities indicated that water quality within the reserves ranged from fair to exceptional. It would appear that improvements of water quality and fish communities within the reserves may require changes in wastewater treatment outfalls and stream drainage land-use practices

16. A Comparison of Soil Biodiversity in Restored Prairie Plots and Agricultural Fields at a Biomass Production Farm in Southeastern Minnesota

Communities of soil-dwelling organisms contribute to soil fertility and nutrient cycling, but conventional farming practices can disturb and reduce these communities. In southeastern Minnesota, some farmers are planting simplified prairie vegetation to produce biomass fuels. Our study was designed to assess the species abundance and diversity of soil invertebrates in plantings of mixed grasses only (MG) and mixed grasses with forbs (MGF) that were planted for use as a biomass fuel source on a farm in southeastern Minnesota in 2007. Abundance and diversity of soil invertebrates also were examined in soils of corn (Zea mays L.) fields grown on the same farm, and in soils of an adjacent prairie managed by the Minnesota Department of Natural Resources (DNR). Six soil samples were collected from each of these 4 landscape types in summer 2010. Soil samples were placed in a Berlese apparatus for 24 h to extract soil invertebrates. Soil invertebrates were most abundant in samples from the DNR prairie (n=156). MG samples had the second highest abundance (n=146), MGF soils had lower abundance (n=87), and corn fields had the fewest invertebrates (n=41). The most abundant taxa in prairie soils included white and brown mites, springtails, and earthworms, whereas springtails and symphylans were the most abundant invertebrates in corn plots. Species diversity (Shannon H\u27) of soil communities differed significantly (analysis of variance: F3,20 = 17.177, P \u3c 0.0001) among landscape types. Tukey’s honestly significant difference test was employed to study any difference in diversity among the 4 landscape units and from this analysis we concluded that DNR and MGF did not differ, nor did MG and MGF reconstructed prairie plots. However, all other comparisons differed significantly in their diversity of soil invertebrates, thus substantiating our findings about abundance. This work has valuable implications for developing more sustainable soil management practices that could serve restoration efforts and adjacent agricultural lands

Thalamocortical relationship in epileptic patients with generalized spike and wave discharges — A multimodal neuroimaging study

AbstractUnlike focal or partial epilepsy, which has a confined range of influence, idiopathic generalized epilepsy (IGE) often affects the whole or a larger portion of the brain without obvious, known cause. It is important to understand the underlying network which generates epileptic activity and through which epileptic activity propagates. The aim of the present study was to investigate the thalamocortical relationship using non-invasive imaging modalities in a group of IGE patients. We specifically investigated the roles of the mediodorsal nuclei in the thalami and the medial frontal cortex in generating and spreading IGE activities. We hypothesized that the connectivity between these two structures is key in understanding the generation and propagation of epileptic activity in brains affected by IGE. Using three imaging techniques of EEG, fMRI and EEG-informed fMRI, we identified important players in generation and propagation of generalized spike-and-wave discharges (GSWDs). EEG-informed fMRI suggested multiple regions including the medial frontal area near to the anterior cingulate cortex, mediodorsal nuclei of the thalamus, caudate nucleus among others that related to the GSWDs. The subsequent seed-based fMRI analysis revealed a reciprocal cortical and bi-thalamic functional connection. Through EEG-based Granger Causality analysis using (DTF) and adaptive DTF, within the reciprocal thalamocortical circuitry, thalamus seems to serve as a stronger source in driving cortical activity from initiation to the propagation of a GSWD. Such connectivity change starts before the GSWDs and continues till the end of the slow wave discharge. Thalamus, especially the mediodorsal nuclei, may serve as potential targets for deep brain stimulation to provide more effective treatment options for patients with drug-resistant generalized epilepsy

Fish assemblage change following the structural restoration of a degraded stream

Decades of anthropogenic pressure have harmed riverscapes throughout North America by degrading habitats and water quality and can result in the extirpation of sensitive aquatic taxa. Local stream restoration projects have increased in frequency, but monitoring is still infrequent. In 2010, Kickapoo Creek in East Central Illinois was subjected to a stream restoration project that included implementation of artificial riffles, riprap, scouring keys, and riparian vegetation. We monitored the restoration efforts for 6years after the restoration through annual sampling efforts at restored and reference sites to determine changes in habitat and fish assemblage using standard habitat sampling and electrofishing techniques. We observed distinct temporal and spatial shifts in physico-chemical parameters along with changes in fish community structure. Although biotic integrity remained moderately low in reference assemblages, restored reaches showed 3-year delay in response to restoration, with biotic integrity positively linked to additional instream habitat and altered channel morphology. Larger substrate sizes, submerged terrestrial vegetation, and newly formed scour pools along with reduced siltation were found in the restored sites, in contrast to the reference sites. These changes resulted in increased species diversity, reduced number of opportunistic species and consequently an overall increase in health of fish communities. We also observed recruitment of habitat specialists and increase in species with reproductive strategies that rely on complex substrates. The results of this study highlight some of the complex dynamics driving reach-scale restoration projects. We demonstrate the usefulness of structural restoration as a management tool to increase biotic integrity through long-term alteration of critical habitat. The delay in the response of species to the restoration efforts emphasizes the need for long-term continuous temporal and spatial monitoring

A Multimetric Assessment of Stream Condition in the Northern Lakes and Forests Ecoregion Using Spatially Explicit Statistical Modeling and Regional Normalization

We sampled fish communities, water temperature, water chemistry, physical habitat, and catchment characteristics for 94 stream sites selected randomly throughout the Northern Lakes and Forests ecoregion and used those data to explicitly model reference conditions and assess ecological stream condition at each site via a regional normalization framework. The streams we sampled were first order through fourth order, and the catchments ranged from 0.9 to 458 km2. We developed multiple linear regression (MLR) models that predicted fish community metrics, water chemistry characteristics, and local physical habitat from catchment characteristics; we used these models to compare existing conditions with the conditions that would be expected based on the regression models. Our results indicated that the fish communities were relatively unimpaired because the catchment variables associated with human‐induced land use change were important in only 1 of the 10 fish metric models. Agricultural land use was a significant variable in the MLR equation for species of Lepomis (sunfish). Agricultural land use and urban land use were both significant variables in all of the MLR models predicting water chemistry variables; urban land use was a significant variable in the MLR model predicting the percent coverage of all instream cover types. Regional normalization indicated that none of the sites were impaired based on fish community attributes. However, our analysis based on water chemistry metrics indicated that 22– 35% of the sites were impaired and that, based on physical habitat, 6–14% of the sites were impaired. A comparison with other published studies of the ecoregion suggested that the regional normalization process correctly characterized stream condition.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141590/1/tafs0697.pd