Extended temperature range ACPS thruster investigation

The successful hot fire demonstration of a pulsing liquid hydrogen/liquid oxygen and gaseous hydrogen/liquid oxygen attitude control propulsion system thruster is described. The test was the result of research to develop a simple, lightweight, and high performance reaction control system without the traditional requirements for extensive periods of engine thermal conditioning, or the use of complex equipment to convert both liquid propellants to gas prior to delivery to the engine. Significant departures from conventional injector design practice were employed to achieve an operable design. The work discussed includes thermal and injector manifold priming analyses, subscale injector chilldown tests, and 168 full scale and 550 N (1250 lbF) rocket engine tests. Ignition experiments, at propellant temperatures ranging from cryogenic to ambient, led to the generation of a universal spark ignition system which can reliably ignite an engine when supplied with liquid, two phase, or gaseous propellants. Electrical power requirements for spark igniter are very low

Interview with Homer and Ruth Blubaugh

Homer and Ruth Blubaugh talk about their Irish heritage, concern about marrying within the family, the Catholic Church, and the family legands. They discuss how they keep in touch with extended family and the Irish community in Knox County.https://digital.kenyon.edu/lt_interviews/1016/thumbnail.jp

Run Like a Kenyan: How to Be An Elite Athlete the Kenyan Way

By observation and statistics, research shows that one dominating elite group in running is the Kenyan distance runners, specifically the Kalenjinethnic group. Many aspects of the Kenyan life were found to contribute to their efficiency and success. Analyzing Kenyan aspects of environment, altitude, society, diet, transportation, motives, and training may reveal possible ways American runners can improve their running

Undercover predators: Vegetation mediates foraging, trophic cascades, and biological control by omnivorous weed seed predators

Weed pressure is the most costly challenge that vegetable growers face, requiring more labor investment than other production inputs. Vertebrate and invertebrate seed predators destroy a large percentage of weed propagules on the soil surface, and their ecosystem services may ease labor requirements for farmers in herbicide-free systems. Cover provided by living vegetation is an important predictor of seed predator activity, and my dissertation takes a comprehensive approach to understanding the behavior, predator, and environment-mediated mechanisms by which cover impacts weed seed predation in crop environments. ^ First, I performed a meta-analysis of 27 studies to quantitatively evaluate what is currently known about seed predation by vertebrates and invertebrates across weed species, crop environments, and seasons (Chapter 1). I found that that seed predators impact some weed species more than others, depending on taxa-specific seed preferences, and that predation rates are minimal in environments entirely void of vegetation. Next, in Chapter 2, I examined the role of vegetative over in determining oviposition preferences of Harpalus pensylvanicus , the most common carabid seed predator in Midwestern crop systems. I found that while adult beetles were strong dispersers and foraged in a variety of habitat types, larvae were less mobile and more vulnerable to disturbance than adults. They were almost exclusively captured in environments characterized by long disturbance intervals and abundant living biomass, emphasizing the importance of cover as perennial refuge for maintaining stable populations of natural enemies. ^ In Chapter 3, I examined omnivorous predator assembly around basic biological resources (cover, seeds, and prey). I found that both predaceous and omnivorous carabid species aggregated in patches of vegetative cover and omnivores assembled in seed patches. None, however responded to prey availability. Using food-specific protein markers, I found that cover doubled the likelihood of detecting seed material, but not prey material in beetles’ digestive tracts. This implies that omnivorous carabids are competent biological control agents of weed seeds, and that provisions of plant cover will not only attract more seed predators, but also induce their seed-feeding behavior. Even though cover directly facilitates seed-feeding, it may also increase the likelihood of intraguild predation on invertebrates by small mammals, as both taxa utilize the same refuge environments. In chapter 4, I quantified the cascading effects of behavior mediated predator-prey interactions over four trophic levels. I found that use of cover by small mammals avoiding predation risk by nocturnal avian predators reduced the activity of carabid seed predators by 50%, but the net effect of small mammals on seed removal was neutral. ^ Finally, in chapter 5, I directly evaluated the utility of seed predation by measuring the effects of seed predators on weed emergence. I simulated seed rain of common lambsquarters, and found that seed predators overcame intense propagule pressure and reduced the germinable seedbank. I found 38% fewer seedlings in seed-augmented plots where seed predators had access, compared to plots where they were excluded. Minimal differences between differential exclusion of vertebrate and invertebrate seed predators suggest that the effect of vertebrates on seed predation is neutral, corroborating evidence from chapter 4. ^ Together, these five chapters enumerate multiple interacting drivers of tropic cascades, with insights of both basic and applied importance. I learned that predator avoidance and intraguild predation interact and simultaneously shape trophic ecology, with distant downstream implications. Because each process is common in nature, it is important to integrate both in future predictions of trophic dynamics. Provisions of vegetative cover can promote weed biological control by both attracting more seed predators and facilitating per-capita seed consumption. While vegetation may also facilitate intraguild predator events, these effects are minimal compared to the strong positive effects of cover on seed predation overall. Thus, cover crops and forage crop rotations can be powerful tools to promote weed biological control, among the numerous other benefits they provide

Concealing the excess of her pleasure : A queer reading of Jane Austen\u27s Northanger Abbey

This queer reading of Jane Austen\u27s Northanger Abbey uses critical frameworks from queer theory, feminist theory, trans theory, and Black Romanticism to analyze female-female relationships between the characters in the novel as a product of the social norms, conventions, and discourses of Romantic-era Britain. By using literary analysis and close reading, I study the many ways in which Northanger Abbey can be read queerly, specifically where gender and sexuality intersect with race and ethnicity. Though queer readings of this novel have been done in the past, my own analysis focuses on female-female relationships and takes race into consideration when I connect the Romantic-era social discourses with the representation of queerness in the novel. One of the ways in which I make these connections is by finding encoded language in which a female-female relationship is implied but not directly stated. This encoded language was a common way for women-loving women to communicate their sexual desires toward other women to very specific audiences—only those who would understand the code in which they spoke. In my research, I discover, explain, and analyze some of this encoded language within Northanger Abbey

The Impacts of Sex-Specific Diets of a Marine Predator on Ecosystem Models

Ecosystem modeling is an increasingly popular method to understand how organisms within ecosystems interact, relying on robust data incorporating important inter- and intraspecies interactions to predict ecosystem changes. However, no study has included sex-specific intrapopulation variation in an ecosystem model. In the well-studied Salish Sea, harbor seals (Phoca vitulina) are an important marine mammal that have significant sex-specific diet variability, which I hypothesized would have indirect effects on other functional groups in the region. Male harbor seals consume a higher diet proportion of salmon, while female harbor seals consume a higher proportion of herring and small demersal fish. I created an ecosystem model of the Salish Sea using the Ecopath framework and calculated predictions of the overall mixed trophic impact that male and female harbor seals each exert on other functional groups. To assess the importance of the sex-specific diets on the indirect impacts, I varied the sex ratio of the harbor seals to simulate the range of sex ratios present spatiotemporally in the Salish Sea. Changing sex ratios also allows me to assess how mixed trophic impacts respond to changing predation pressure from each sex. Male harbor seals were predicted to have a strong negative impact on raptors and a strong positive impact on piscivorous seabirds, neither of which are part of the harbor seal diets, while female harbor seals had a very low impact on these groups. There was a negligible difference in impact on herring despite having the largest difference in diet contribution between male and female harbor seals. Male harbor seals consistently exerted a stronger negative impact on Pacific salmon than females, even when females were predicted to consume a greater proportion of Pacific salmon production. The results suggest that indirect trophic cascades contribute to harbor seal sex-specific impacts on other groups, rather than predation alone. These sex-specific impacts may be lost in models that do not account for sex-specific diet variation within the harbor seal population in the Salish Sea

Is bicarbonate in Photosystem II the equivalent of the glutamate ligand to the iron atom in bacterial reaction centers?

Photosystem II of oxygen-evolving organisms exhibits a bicarbonate-reversible formate effect on electron transfer between the primary and secondary acceptor quinones, QA and QB. This effect is absent in the otherwise similar electron acceptor complex of purple bacteria, e.g. Rhodobacter sphaeroides. This distinction has led to the suggestion that the iron atom of the acceptor quinone complex in PS II might lack the fifth and sixth ligands provided in the bacterial reaction center (RC) by a glutamate residue at position 234 of the M-subunit in Rb. sphaeroides,RCs (M232 in Rps. viridis). By site-directed mutagenesis we have altered GluM234 in RCs from Rb. sphaeroides, replacing it with valine, glutamine and glycine to form mutants M234EV, M234EQ and M234EG, respectively. These mutants grew competently under phototrophic conditions and were tested for the formate-bicarbonate effect. In chromatophores there were no detectable differences between wild type (Wt) and mutant M234EV with respect to cytochrome b-561 reduction following a flash, and no effect of bicarbonate depletion (by incubation with formate). In isolated RCs, several electron transfer activities were essentially unchanged in Wt and M234EV, M234EQ and M234EG mutants, and no formate-bicarbonate effect was observed on: (a) the fast or slow phases of recovery of the oxidized primary donor (P+) in the absence of exogenous donor, i.e., the recombination of P+QA− or P+QB−, respectively; (b) the kinetics of electron transfer from QA− to QB; or (c) the flash dependent oscillations of semiquinone formation in the presence of donor to P+ (QB turnover). The absence of a formate-bicarbonate effect in these mutants suggests that GluM234 is not responsible for the absence of the formate-bicarbonate effect in Wt bacterial RCs, or at least that other factors must be taken into account. The mutant RCs were also examined for the fast primary electron transfer along the active (A-)branch of the pigment chain, leading to reduction of QA. The kinetics were resolved to reveal the reduction of the monomer bacteriochlorophyll (τ = 3.5 ps), followed by reduction of the bacteriopheophytin (τ = 0.9 ps). Both steps were essentially unaltered from the wild type. However, the rate of reduction of QA was slowed by a factor of 2 (τ = 410 ± 30 and 47 ± 30 ps for M234EQ and M234EV, respectively, compared to 220 ps in the wild type). EPR studies of the isolated RCs showed a characteristic g = 1.82 signal for the QA semiquinone coupled to the iron atom, which was indistinguishable from the wild type. It is concluded that GluM234 is not essential to the normal functioning of the acceptor quinone complex in bacterial RCs and that the role of bicarbonate in PS II is distinct from the role of this residue in bacterial RCs

Can Bedside Ultrasound Inferior Vena Cava Measurements Accurately Diagnose Congestive Heart Failure in the Emergency Department? A Clin-IQ

Congestive heart failure (CHF) is a major cause of morbidity and mortality. Early diagnosis of CHF in patients presenting to the emergency department with undifferentiated dyspnea would allow clinicians to begin appropriate treatment more promptly. Current guidelines recommend B-type natriuretic peptide (BNP) levels for more accurate diagnosis of CHF in dyspneic patients. Although BNP levels are relatively inexpensive, the test is not usually performed at bedside and results may take up to an hour or more. BNP also may have a “gray zone” in which the values can neither confirm nor rule out CHF. BNP has a reported sensitivity of 87% and specificity of 74% at a cutoff of 400 pg/ml. Studies investigating bedside ultrasound inferior vena cava (IVC) measurements for identifying CHF report a specificity of 84% to 96% and sensitivity values ranging from 37% to 93%, depending on the study. Given that ultrasound IVC measurements are performed at bedside and results are available rapidly, it is reasonable to evaluate whether ultrasound IVC measurements obtained by appropriately trained emergency department clinicians, alone or in combination with BNP, may increase diagnostic accuracy of CHF

Demand-Controlled Ventilation Energy Savings for Air Handling Unit

Heat, cooling, and ventilation units are major energy consumers for commercial buildings, consuming as much as 50% of a building’s total annual power usage. Management of an air handling system’s energy is a key factor of reducing the energy costs and carbon dioxide (CO2) emissions that are associated with the demand when ventilating and conditioning the air in a building. One issue is that buildings are frequently over ventilated as a full assessment of the air handling unit (AHU) data is not evaluated by building operators. There are multiple variables that account for energy consumption of the AHU which need to be monitored by building operators. In order to assess the demand, it is required that the CO2 levels of the occupied zones be measured, and the outdoor air ventilation rate be adjusted based on real-time CO2. The concept of an energy management system and its characteristics are defined in respect to use with an AHU system. The prototype system used for the research is demonstrated and key data analyzed using real-time data collection. The goal of the research is to assess the number of CO2 sensors needed to accurately measure the demand-based needs for ventilation and provide review of the data required to monitor the AHU energy. Findings indicate that no more than one CO2 sensor would be required for a large lecture hall