2,226 research outputs found

    Research on techniques for laser ranging to optical corner reflectors on the moon. Research on laser techniques and single photo-electron detection and timing

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    Experimental studies using a pulsed LED, Cerenkov source, and a 100 ps laser were made of various photomultipliers and discriminator combinations. In addition, a new type of neodymium-YAG frequency doubled laser was used as the basis for the development of a stable, short pulse, high repetition rate laser system. This laser was then used in conjunction with atomic clocks to study the effect of gravitational potential on elapsed time. Avenues to promote the development of international cooperation in the area of lunar laser ranging were also explored

    Laser beam pointing tests

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    Laser beam pointing tests for lunar communication and rangefinding and tracking using Surveyor 7 vidicon camer

    Refutation of C. W. Misner's claims in his article "Yilmaz Cancels Newton''

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    It is shown that an article by C. W. Misner contains serious errors. In particular, the claim that the Yilmaz theory of gravitation cancels the Newtonian gravitational interaction is based on a false premise. With the correct premise the conclusion of the article regarding the absence of gravitational interactions applies to general relativity and not to the Yilmaz theory.Comment: 12 pages, LaTeX, submitted to Il Nuovo Ciment

    A New Course in Defense Manufacturing – An Introduction to Shipbuilding

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    This paper discusses the development and deployment of a new course in DMEI (Defense Manufacturing Engineering Innovation) titled, “Introduction to Shipbuilding.” This course has been taught using Zoom since 2021 at both the University of Texas Rio Grande Valley, a Hispanic Serving Institution, and Virginia State University, a Historically Black University. After a brief literature review, an outline of the course is presented with topics including the maritime market for shipbuilding, economics of shipbuilding, the classification agencies, metallurgy and welding processes, ship structure and assembly, shipyard layout, accuracy control, and shipbuilding planning and scheduling. Difficulties in obtaining an appropriate textbook and the use of guest lecturers are discussed. Student survey data is presented, and conclusions are drawn about this course

    A Case Study of Athletic Training Educators\u27 Sports-Care Responsibilities, Service, and Professional Advancement in Athletic Training Education Programs

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    The purpose of this study was to examine the (1) extent of athletic training faculty members, who bear additional duties for intercollegiate sports care, (2) the beliefs of the faculty members who have intercollegiate sports care responsibilities related to these duties being credited for professional advancement, (3) the beliefs of faculty members related to having sport care responsibilities as part of their employment, and (4) faculty perceptions of intercollegiate sports care responsibilities upon promotion, tenure and contract renewal. A sample of 655 certified athletic trainers was identified by the Board of Certification with the primary occupation designation of educator from a population of 7052 certified members who identified themselves as working in the college and university setting. There were 255 surveys returned for a response rate of 38%. The study utilized descriptive statistics, correlations and emergent category analysis. Findings indicate that only 22% of athletic training educators surveyed had institutional sports care responsibilities. These athletic training educators who had institutional sports care responsibilities overwhelmingly indicated that these responsibilities should be counted toward institutional service credit for professional advancement. Reasons given include that (a) sports care responsibilities are part of the job, (b) there is not enough time for other activities, (c) it is a part of supervising students, and (d) it is a service to school and profession. Athletic training academic faculty members overwhelming believe that they should not have institutional sports care responsibilities. The reasons given for this were (a) lack of balance in responsibilities, (b) no time for sports care responsibilities, and (c) needing to spend more time on academic activities. Athletic training clinical faculty believed that they should have some sort of institutional sports care responsibilities. The reasons given were (a) relevance to the job and teaching, (b) an expectation to do clinical work, and (c) faculty can be active, but not necessarily with the institutions sports teams. Overall, athletic training faculty members do not believe that having sports care responsibilities affect one’s chances of professional advancement

    Cosmological test of the Yilmaz theory of gravity

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    We test the Yilmaz theory of gravitation by working out the corresponding Friedmann-type equations generated by assuming the Friedmann-Robertson-Walker cosmological metrics. In the case that space is flat the theory is consistent only with either a completely empty universe or a negative energy vacuum that decays to produce a constant density of matter. In both cases the total energy remains zero at all times, and in the latter case the acceleration of the expansion is always negative. To obtain a more flexible and potentially more realistic cosmology, the equation of state relating the pressure and energy density of the matter creation process must be different from the vacuum, as for example is the case in the steady-state models of Gold, Bondi, Hoyle and others. The theory does not support the cosmological principle for curved space K =/= 0 cosmological metrics

    The far field diffraction pattern for corner reflectors with complex reflection coefficients

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    The far field diffraction pattern of a geometrically perfect corner reflector is examined analytically for normally incident monochromatic light. The states of polarization and the complex amplitudes of the emerging light are expressed through transformation matrices in terms of those of the original incident light for each sextant of the face in a single coordinate system. The analytic expression of the total diffraction pattern is obtained for a circular face. This expression consists of three component functions in addition to the basic Airy function. The coefficient of each function is expressed in terms of complex coefficients of reflectance of the reflecting surface. Some numerical results for different reflecting surfaces, including total internal reflection, are presented. The iso-intensity contours of the diffraction pattern evaluated from the analytical expressions for an uncoated solid corner reflector are also presented along with the photographs of the pattern

    South Dakota Grain Production: Yesterday and Tomorrow

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    This bulletin provides an analysis of past and future grain production in the state of South Dakota, and examines trends between the years of 1963 and 1978

    Benefits of Implementing Automated Costing in a Small Machine Shop: A Case Study

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    Knowledge based cost estimating systems are available, but is there a lower limit to their applicability in an industrial environment?  This paper answers this question by examining a knowledge based cost estimating expert system application in a small machine shop.  Differences between the traditional experienced-based system currently employed and the automated system are studied.  Data is gathered to analyze time effectiveness, accuracy, and payback of the software.  Data from seventy part models is recorded to study the time experiment and data from fifty part models is used to study accuracy and consistency.The results indicate that the software is faster than traditional quoting systems; however, the payback point is high. Also, results show that the software has a smaller average time to manufacture percent difference between the automated system and the actual time to manufacture (TTM) compared to the percentage difference between the traditional TTM and actual TTM. Standard deviation for the automation is also less, implying better consistency.  As a result, the attractiveness of the automated system in the limiting case of a small machine shop rests with significantly improved accuracy and consistency rather than payback.

    Partnering with a Middle School: Making a Space for Rural Middle School Student Voice

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    In this Practitioner Perspective, we explore two boundary spanning field experiences provided to teacher candidates to center middle school student voice and lived experiences supported by a school-university partnership. Surveys and teacher candidate reflections provided perspectives on both experiences and how these connected to coursework. We describe how both experiences influenced teacher candidates, enhancing their understanding of young adolescents, and bridging the theory-practice gap. Lessons learned through these experiences and future recommendations are included
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