3,577 research outputs found

    Ecological effects and environmental fate of solid rocket exhaust

    Get PDF
    Specific target processes were classified as to the chemical, chemical-physical, and biological reactions and toxic effects of solid rocket emissions within selected ecosystems at Kennedy Space Center. Exposure of Citris seedlings, English peas, and bush beans to SRM exhaust under laboratory conditions demonstrated reduced growth rates, but at very high concentrations. Field studies of natural plant populations in three diverse ecosystems failed to reveal any structural damage at the concentration levels tested. Background information on elemental composition of selected woody plants from two terrestrial ecosystems is reported. LD sub 50 for a native mouse (peromysous gossypinus) exposed to SRM exhaust was determined to be 50 ppm/g body weight. Results strongly indicate that other components of the SRM exhaust act synergically to enhance the toxic effects of HCl gas when inhaled. A brief summary is given regarding the work on SRM exhaust and its possible impact on hatchability of incubating bird eggs

    Competencies Related to Marine Mechatronics Education

    Get PDF
    Recent changes in the needs of the military have caused the U.S. Navy to spend more time out to sea. Longer deployments limit the time available for performing maintenance and for training their technicians. The Navy is also steadily reducing the number of sailors manning each vessel, therefore requiring more automated systems to keep the ships at sea and in total readiness. To meet this need, industrial automation systems are being investigated as replacements and upgrades for the military systems that have been used for years in warship designs. This will require ship repair partners, both military and civilian, to work with unfamiliar equipment (in the current trades mix) that was not designed for installation in such a harsh environment. Although the industrial automation industry has been using these systems for years, there is a shortage of technicians in the maritime industry that understand mechatronics systems. Hence, there is a need to better prepare technicians to install and repair these systems since it is a complete change to the previous design of warship systems. This paper will present an overview of competencies related to one such career, and overview the relation between mechatronics engineering and marine engineering. It will also present the current state of the different educational levels, starting from high school and continuing onto technician and undergraduate education and programs

    Developing a Curriculum for Marine Mechatronics Technicians

    Get PDF
    A growing trend within the U.S. Navy is to streamline operations by deploying ships with less sailors, who are more highly skilled technicians that are trained to do a wide array of jobs. Modern ships also include various automated systems that require more highly skilled technicians for maintenance. Outdated warship designs are now being replaced with industrial grade automation equipment. Such equipment is being used in warships that encounter harsher environments than what exists in the civilian industry. Hence, there is a need for training in regards to industrial grade automation equipment for military and civilian ship repair partners. Marine mechatronics technicians will be trained to maintain these modern complex warship systems. For that purpose, the team of marine mechatronics experts participated in a two day long DACUM workshop at a community college (blind review). The workshop\u27s main purpose was to identify all competencies, skills, tools, and behaviors necessary for the specific job of a marine mechatronics technician

    International Society of Sports Nutrition position stand: beta-alanine

    Get PDF
    Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the mechanisms and use of beta-alanine supplementation. Based on the current available literature, the conclusions of the ISSN are as follows: 1) Four weeks of beta-alanine supplementation (4โ€“6 g daily) significantly augments muscle carnosine concentrations, thereby acting as an intracellular pH buffer; 2) Beta-alanine supplementation currently appears to be safe in healthy populations at recommended doses; 3) The only reported side effect is paraesthesia (tingling), but studies indicate this can be attenuated by using divided lower doses (1.6 g) or using a sustained-release formula; 4) Daily supplementation with 4 to 6 g of beta-alanine for at least 2 to 4 weeks has been shown to improve exercise performance, with more pronounced effects in open end-point tasks/time trials lasting 1 to 4 min in duration; 5) Beta-alanine attenuates neuromuscular fatigue, particularly in older subjects, and preliminary evidence indicates that beta-alanine may improve tactical performance; 6) Combining beta-alanine with other single or multi-ingredient supplements may be advantageous when supplementation of beta-alanine is high enough (4โ€“6 g daily) and long enough (minimum 4 weeks); 7) More research is needed to determine the effects of beta-alanine on strength, endurance performance beyond 25 min in duration, and other health-related benefits associated with carnosine

    Elliptic curves, modular forms, and sums of Hurwitz class numbers

    Get PDF
    Let H(N) denote the Hurwitz class number. It is known that if pp is a prime, then {equation*} \sum_{|r|<2\sqrt p}H(4p-r^2) = 2p. {equation*} In this paper, we investigate the behavior of this sum with the additional condition rโ‰กc(modm)r\equiv c\pmod m. Three different methods will be explored for determining the values of such sums. First, we will count isomorphism classes of elliptic curves over finite fields. Second, we will express the sums as coefficients of modular forms. Third, we will manipulate the Eichler-Selberg trace for ula for Hecke operators to obtain Hurwitz class number relations. The cases m=2,3m=2,3 and 4 are treated in full. Partial results, as well as several conjectures, are given for m=5m=5 and 7.Comment: Preprint of an old pape
    • โ€ฆ
    corecore