7,890 research outputs found

    Report on visit to four North American airlines

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    The object of the visits was to discuss the current state-of-the-art with the Engineering Departments of several North American airlines which were known to be leading the field in the application of certain advanced techniques. In the limited time available it was decided to confine the talks mainly to those topics on which the chosen operators were known to have had unique experience. This note is presented in chronological sequence and is only intended to be a record of the information gathered; no derivations, or comparisons with other operators, are made. United Air Lines were visited first and reliability programmes are detailed, although the application of critical path techniques to aircraft and engine overhaul is summarised. Continental Air Lines are noted for their use of the continuous maintenance philosophy, and this is reported next. The third visit was to Air Canada where talks ranged from the applications of operations research and electronic data processing (EDP) techniques to aircraft evaluation procedures. Finally the PanAm aircraft system reliability programme is reviewed, together with a note on their general LDP engineering and maintenance activities. A bibliography is given, although it should be appreciated that some of the items listed contain information which may be commercially secure

    Method of measuring thermal conductivity of high performance insulation

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    Method accurately measures the thermal conductivity of high-performance sheet insulation as a discrete function of temperature. It permits measurements to be made at temperature drops of approximately 10 degrees F across the insulation and ensures measurement accuracy by minimizing longitudinal heat losses in the system

    A REAL OPTIONS APPROACH TO INVESTMENT ANALYSIS OF AUTOMATIC MILKING SYSTEMS

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    Automatic, or robotic, milking systems are beginning to be introduced to U.S. dairy farmers. This paper employs an ex ante approach to real options investment analysis of automatic milking systems.Livestock Production/Industries,

    A Real Options Analysis of Automatic Milking Systems

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    Automatic, or robotic, milking systems have the potential to significantly change the way milk is produced on U.S. dairy farms. However, there is a high degree of uncertainty associated with adoption of this new technology. A real options approach is used to analyze the decision to replace an operational milking system with an automatic milking system. The most important source of uncertainty is shown to be the length of the technology's useful life. Under our assumptions, the automatic system is always an optimal investment if it is certain that it will last longer than the operational system being replaced.Livestock Production/Industries,

    Some thoughts on a proposed in-flight experiment to study the effect of external noise on a swept laminarised wing

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    A transducer-horn arrangement has been suggested as a suitable noise source to be installed in the Lancaster aircraft so that the Handley-Page suction fin could be subjected to large acoustical disturbances. The object of this note is to clarify this proposal with a view to recommending actions to be taken

    A measurement of the radiated noise on a subsonic jet aircraft in gliding flight

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    The noise radiated from a gliding subsonic jet aircraft was measured in flight by a probe microphone installed in a ‘laminarised’ boom projecting from the fin of the aircraft. As the signal associated with the windmilling turbines was predominant even at flight speeds near the aircraft's limiting Mach number, it was not possible to relate the noise radiated from the turbulent boundary layers to flight speed. The measured sound pressure levels in the frequency band 4o c/s to 15 kc/s, for Mach numbers between 0.24 and 0.66 at an altitude of 20,000 ft., were in the range from 110 to 115 decibels relative to 0.0002 ubar. A calculation of the radiated noise from the boundary layers gave overall levels of 85 to 120 db relative to 0.0002 bar at the microphone position on the aircraft for the same range of flight conditions

    Advanced technology applications for second and third general coal gasification systems

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    The historical background of coal conversion is reviewed and the programmatic status (operational, construction, design, proposed) of coal gasification processes is tabulated for both commercial and demonstration projects as well as for large and small pilot plants. Both second and third generation processes typically operate at higher temperatures and pressures than first generation methods. Much of the equipment that has been tested has failed. The most difficult problems are in process control. The mechanics of three-phase flow are not fully understood. Companies participating in coal conversion projects are ordering duplicates of failure prone units. No real solutions to any of the significant problems in technology development have been developed in recent years

    Cold Pavement and Two People

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    In lieu of an abstract, below is the essay\u27s first paragraph. On that brisk February evening Elizabeth and I stood side by side on the Greyhound station waiting platform. It was so cold I thought my feet and fingertips would freeze. I could see no reason why everyone had to wait so long to board the bus. Although I wasn\u27t enjoying it at all, it didn\u27t seem to bother Elizabeth; she seemed very comfortable as she held tightly onto my arm. It struck me as if zero, waiting, and our coming separation weren\u27t in her mind at all; I knew she was trying not to think of them. I felt bad that I would be back home in fifteen minutes and she had a twelve-hour bus ride ahead of her. In spite of being very cold and impatient, I thought of these things. I knew my love for her was as cold as the pavement and empty air around us. This was the reason that I shivered heavily underneath my coat and gloves. I knew why she did not shiver as she stood so straight in her high heels. I knew why she held my arm more tightly and that she was probably looking at me and smiling. I just couldn\u27t look in her eyes very long. Everytime l did her love seemed to come forth in that look, and I knew it must return injured; it had never met what it had itself

    Improvements in estimating proportions of objects from multispectral data

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    Methods for estimating proportions of objects and materials imaged within the instantaneous field of view of a multispectral sensor were developed further. Improvements in the basic proportion estimation algorithm were devised as well as improved alien object detection procedures. Also, a simplified signature set analysis scheme was introduced for determining the adequacy of signature set geometry for satisfactory proportion estimation. Averaging procedures used in conjunction with the mixtures algorithm were examined theoretically and applied to artificially generated multispectral data. A computationally simpler estimator was considered and found unsatisfactory. Experiments conducted to find a suitable procedure for setting the alien object threshold yielded little definitive result. Mixtures procedures were used on a limited amount of ERTS data to estimate wheat proportion in selected areas. Results were unsatisfactory, partly because of the ill-conditioned nature of the pure signature set
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