15,064 research outputs found

    Silicone modified resins for graphite fiber laminates

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    The development of silicon modified resins for graphite fiber laminates which will prevent the dispersal of graphite fibers when the composites are burned is discussed. Eighty-five silicone modified resins were synthesized and evaluated including unsaturated polyesters, thermosetting methacrylates, epoxies, polyimides, and phenolics. Neat resins were judged in terms of Si content, homogeneity, hardness, Char formation, and thermal stability. Char formation was estimated by thermogravimetry to 1,000 C in air and in N2. Thermal stability was evaluated by isothermal weight loss measurements for 200 hrs in air at three temperatures. Four silicone modified epoxies were selected for evaluation in unidirectional filament wound graphite laminates. Neat samples of these resins had 1,000 C char residues of 25 to 50%. The highest flexural values measured for the laminates were a strength of 140 kpsi and a modulus of 10 Mpsi. The highest interlaminar shear strength was 5.3 kpsi

    Silicone modified resins for graphite fiber laminates

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    Six silicone modified resins were selected for evaluation in unidirectional filament wound graphite laminates. Neat samples of these resins had 1,000 C char residues of 6-63%. The highest flexural values measured for the laminates were a strength of 1,220 MPa and a modulus of 105 GPa. The highest interlaminar shear strength was 72 MPa

    Synthesis of pyrrone polymers, 21 June 1967 - 21 June 1968

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    Synthesis of pyrrone polymers by reactions of dianhydride and diacetoamido diamines or with tetramin

    Observation of the stray field of thin film magnetic tips using electron holography

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    The stray field around thin film ferromagnetic tips employed for magnetic force microscopy has been revealed using electron holography. The experimental phase difference maps are in good agreement with simulations. Quantitative flux measurements of the leakage field are obtained

    Design of prototype charged particle fog dispersal unit

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    The unit was designed to be easily modified so that certain features that influence the output current and particle size distribution could be examined. An experimental program was designed to measure the performance of the unit. The program described includes measurements in a fog chamber and in the field. Features of the nozzle and estimated nozzle characteristics are presented

    Charged particle concepts for fog dispersion

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    Charged particle techniques hold promise for dispersing warm fog in the terminal area of commercial airports. This report focuses on features of the charged particle technique which require further study. The basic physical principles of the technique and the major verification experiments carried out in the past are described. The fundamentals of the nozzle operation are given. The nozzle characteristics and the theory of particle charging in the nozzle are discussed, including information from extensive literature on electrostatic precipitation relative to environmental pollution control and a description of some preliminary reported analyses on the jet characteristics and interaction with neighboring jets. The equation governing the transfer of water substances and of electrical charge is given together with a brief description of several semi-empirical, mathematical expressions necessary for the governing equations. The necessary ingredients of a field experiment to verify the system once a prototype is built are described

    Darlin\u27

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    [Verse] ‘Tis twilight, and shows are fallin’, Darlin’, darlin’, ‘Tis twilight, and to you I’m callin’, Darlin’, darlin’. The night winds are sighin’, for we’re far apart, There’s no need denyin’ the teardrops that start, For I know that your absence is breakin’ my heart, Darlin’ darlin’. I know there is no need o’ sighin’, Darlin’, darlin’, But somehow my heart keeps a cryin’, Darlin’, darlin’. The voice of my heart cryin’ out for its all Will sound thro’ the deepenin’ shadows that fall, In hoped that you some day will answer my call, Darlin’, darlin’

    How to Reduce the Cost of Selling

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