1,240 research outputs found

    Chemistry Characterization of Jet Aircraft Engine Particulate by XPS: Results from APEX III

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    This paper reports XPS analysis of jet exhaust particulate from a B737, Lear, ERJ, and A300 aircraft during the APEX III NASA led field campaign. Carbon hybridization and bonding chemistry are identified by high-resolution scans about the C1s core-shell region. Significant organic content as gauged by the sp3/sp2 ratio is found across engines and platforms. Polar oxygen functional groups include carboxylic, carbonyl and phenol with combined content of 20 percent or more. By lower resolution survey scans various elements including transition metals are identified along with lighter elements such as S, N, and O in the form of oxides. Burning additives within lubricants are probable sources of Na, Ba, Ca, Zn, P and possibly Sn. Elements present and their percentages varied significantly across all engines, not revealing any trend or identifiable cause for the differences, though the origin is likely the same for the same element when observed. This finding suggests that their presence can be used as a tracer for identifying soots from aircraft engines as well as diagnostic for monitoring engine performance and wear

    Application of Carbon Based Nano-Materials to Aeronautics and Space Lubrication

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    The tribology program at NASA Glenn Research Center in Cleveland, Ohio, is investigating carbon based nano-particles for their potential in advanced concept lubrication products. Service conditions range from high temperature atmospheric to low temperature vacuum. Some of the lubricants and surface coatings of tribological significance that we have evaluated include neat nano-particles, both grown in-situ and as bulk material deposited on the substrate, and nano-particles dispersed in oils which are all highly substrate interactive. We discuss results of testing these systems in a spiral orbit tribometer (SOT) and a unidirectional pin-on-disc (PoD) tribometer. A nano-onions/Krytox mixture evaluated as a lubricant for angular contact bearings in air caused a marked lowering of the coefficient of friction (CoF) (0.04 to 0.05) for the mixture with an eight-fold improvement in lifetime over that of the Krytox alone. In vacuum, no effect was observed from the nano-onions. Multi-walled nanotubes (MWNT) and graphitized MWNT were tested under sliding friction in both air and vacuum. The MWNT which were grown in-situ oriented normal to the sliding surface exhibited low CoF (0.04) and long wear lives. Bulk MWNT also generate low CoF (0.01 to 0.04, vacuum; and 0.06, air) and long wear life (>1 million orbits, vacuum; and >3.5 million, air). Dispersed graphitized MWNT were superior to MWNT and both were superior to aligned MWNT indicating that orientation is not an issue for solid lubrication. Single-walled nanotubes (SWNT) were modified by cutting into shorter segments and by fluorination. All SWNTs exhibited low CoF in air, with good wear lives. The SWNT with slight fluorination yielded an ultra-low CoF of 0.002 although the best wear life was attributed to the nascent SWNT

    Implementing a Multi-Tiered System of Supports

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    This action research project examined the implementation of a multi-tiered system of supports in a math classroom at a private, Christian suburban school in central Iowa. The researcher utilized the four essential indicators of MTSS to support a small group of four students who were the participants in her study. The intervention targeted the seventh grade math skills of simplifying expressions and solving equations using various methods. Analysis of the triangulated data showed growth in each of the students at varied amounts. Findings of the study suggest that students need consistent, protected Tier 2 intervention to make the most significant progress towards grade level standards

    Honors College Retention in the College of Agriculture, Food and Environmental

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    The College of Agriculture, Food and Environmental Sciences (CAFES) at South Dakota State University (SDSU) has the second lowest Honors College student enrollment compared to all other colleges in the university. This study explores factors that deter CAFES students from enrolling or continuing with Honors and potential opportunities to encourage enrollment and retention. A QuestionPro survey and focus groups were utilized in collecting responses from first-year CAFES students on their awareness of the Honors College’s automatic enrollment, factors that deter students from pursuing Honors, and opportunities. Survey responses (n=59) were reported as percentages. Randomized focus groups were created from the pool of survey participants and split into Honors and non-Honors sections. Data from both surveys and focus groups indicate the main factors deterring CAFES students from pursuing Honors include class schedule concerns, a lack of necessity for Honors in their intended career paths in agriculture, and a lack of CAFES-specific Honors courses. Furthermore, a gap in knowledge about the Honors College and its enrollment qualifications exists amongst CAFES students; a majority of students would potentially pursue Honors if more opportunities within CAFES were offered, such as informational sessions and Honors-specific CAFES courses. This supports the proposed curriculum requirements the Honors College is in the process of obtaining approval for and suggests that adding CAFES-specific Honors courses may help improve Honors College participation by CAFES students.https://openprairie.sdstate.edu/honors_isp/1015/thumbnail.jp

    Sex, friends, and disease: social ecology of elk (Cervus elaphus) with implications for pathogen transmission

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    Many mammals are social. The most basic social behaviour is when the actions of one conspecific are directed toward another, what we call the ‘dyadic interaction’. Both intrinsic and extrinsic factors may affect an individual’s propensity to interact with other members of a population. I used a social cervid, elk (Cervus elaphus), as a model species to test the importance of intrinsic and extrinsic factors of sociality on dyadic interactions. Dyadic interactions not only form the basis for social structure and information transfer within a population, but are also routes of pathogen transmission. My objective in this thesis was thus twofold: to improve our understanding of sociobiology, but also to gain insight into how sociality may underlie the transmission of communicable wildlife disease. I used a hierarchical, autecological approach from DNA, through individual, dyad, group, subpopulation, and ultimately population to explore the effects of intrinsic factors (e.g., sex and pairwise genetic relatedness) and extrinsic factors (e.g., season, conspecific density, habitat, and elk group size) on sociality. Elk in Riding Mountain National Park (RMNP), Manitoba, Canada, are exposed to the causal agent of bovine tuberculosis (Mycobacterium bovis; TB); however, spatial variation in apparent disease prevalence suggests that TB can only persist in one subpopulation within the Park. Using the natural RMNP system and a captive elk herd that I manipulated, I explored factors that influence interaction rates and durations (as a proxy for pathogen transmission) among elk. Sexual segregation in elk results in seasonal and sex-based differences in interaction rate and duration; with interactions peaking in autumn-winter for both sexes. Female-female dyads interact more frequently than male-male dyads. However, male-male dyads interact for longer durations than do female-female dyads. Interaction rate and duration did not covary with pairwise relatedness. Conspecific density also had sex-specific results for interaction rate and duration. Whereas male-male dyadic interaction rates increase with density, female-female dyads increase until they reach a threshold and subsequently reduce their interaction rates at high density. I observed density dependence in interaction rates in experimental trials and from field data. Furthermore, social networks revealed that social familiarity (i.e., heterogeneity of interactions) can be both frequency- and- density dependent depending on the strength of the relationship (i.e., number of repeat interactions). Density also affected the likelihood that an interaction would occur; however, this was modified by vegetation association used by elk. My results reveal several ecological and evolutionary implications for information transfer and pathogen transmission. In particular, I show that seasonal inter-sex routes of transfer may exist and that transfer is likely to be density-dependent. Finally, I conclude that such transfer is modified by available resources

    Turning light into a liquid via atomic coherence

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    We study a four level atomic system with electromagnetically induced transparency with giant χ(3)\chi^{(3)} and χ(5)\chi^{(5)} susceptibilities of opposite signs. This system would allow to obtain multidimensional solitons and light condensates with surface tension properties analogous to those of usual liquids

    Professional Decision-Making in Research (PDR): The validity of a new measure

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    In this paper, we report on the development and validity of the Professional Decision-Making in Research (PDR) measure, a vignette-based test that examines decision-making strategies used by investigators when confronted with challenging situations in the context of empirical research. The PDR was administered online with a battery of validity measures to a group of NIH-funded researchers and research trainees who were diverse in terms of age, years of experience, types of research, and race. The PDR demonstrated adequate reliability (alpha = .84) and parallel form correlation (r = .70). As hypothesized, the PDR was significantly negatively correlated with narcissism, cynicism, moral disengagement, and compliance disengagement; it was not correlated with socially desirable responding. In regression analysis, the strongest predictors of higher PDR scores were low compliance disengagement, speaking English as a native language, conducting clinical research with human subjects, and low levels of narcissism. Given that the PDR was written at an eighth grade reading level to be suitable for use with English as a second language participants and that only one-fourth of items focused on clinical research, further research into the possible roles of culture and research ethics training across specialties is warranted. This initial validity study demonstrates the potential usefulness of the PDR as an educational outcome assessment measure and a research instrument for studies on professionalism and integrity in research

    Processing of Nanostructured Devices Using Microfabrication Techniques

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    Systems and methods that incorporate nanostructures into microdevices are discussed herein. These systems and methods can allow for standard microfabrication techniques to be extended to the field of nanotechnology. Sensors incorporating nanostructures can be fabricated as described herein, and can be used to reliably detect a range of gases with high response

    SDSU Cow/Calf Teaching and Research Unit

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    The SDSU Cow/Calf Unit (CCU) is a multi‐purpose facility that provides resources for Animal Science courses and research projects. Cattle produced at the facility are also utilized by Little International, Block and Bridle, and livestock judging teams. The facility is managed by Kevin Vander Wal and generally employs 4 to 5 undergraduate students
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