755 research outputs found

    Computer program for definition of transonic axial-flow compressor blade rows

    Get PDF
    Particular type of blade element used has two segments which have centerlines and surfaces described by constant change of angle with path distance on cone. Program is result of rework of earlier program to give major gains in accuracy, reliability and speed. It also covers more steps of overall compressor design procedure

    FORTRAN program for computing coordinates of circular-arc, single and tandem, turbine and compressor, blade sections on a plane

    Get PDF
    Coordinates for circular arc blade section of aircraft high speed compressor gas turbines were computed using FORTRAN 4 program. Aerodynamic configurations studied include single segment airfoils, airfoils with slots, and mutiple segment tandem arranged airfoil

    Computer program to determine roots of polynomials by ratio of successive derivatives

    Get PDF
    High speed computing finds roots of polynomials with real number coefficients. Ratios of successive polynomial derivatives approach provides accurate roots-of-polynomial computer programs with very high reliability. With derivative ratio method, root analysis can still be done even though the polynomial and its lower order derivatives cannot be evaluated with sufficient accuracy

    Computer program for aerodynamic and blading design of multistage axial-flow compressors

    Get PDF
    A code for computing the aerodynamic design of a multistage axial-flow compressor and, if desired, the associated blading geometry input for internal flow analysis codes is presented. Compressible flow, which is assumed to be steady and axisymmetric, is the basis for a two-dimensional solution in the meridional plane with viscous effects modeled by pressure loss coefficients and boundary layer blockage. The radial equation of motion and the continuity equation are solved with the streamline curvature method on calculation stations outside the blade rows. The annulus profile, mass flow, pressure ratio, and rotative speed are input. A number of other input parameters specify and control the blade row aerodynamics and geometry. In particular, blade element centerlines and thicknesses can be specified with fourth degree polynomials for two segments. The output includes a detailed aerodynamic solution and, if desired, blading coordinates that can be used for internal flow analysis codes

    FORTRAN program for computing coordinates of circular arc single and tandem turbomachinery blade sections on a plane

    Get PDF
    FORTRAN program for computing coordinates of circular arc single and tandem turbomachinery blade sections on plan

    Off-design correlation for losses due to part-span dampers on transonic rotors

    Get PDF
    Experimental data from 10 transonic fan rotors were used to correlate losses created by part-span dampers located near the midchord position on the rotor blades. The design tip speed of these rotors varied from 419 to 425 m/sec, and the design pressure ratio varied from 1.6 to 2.0. Additional loss caused by the dampers for operating conditions between 50 and 100 percent of design speed were correlated with relevant aerodynamic and geometric parameters. The resulting correlation predicts the variation of total-pressure-loss coefficient in the damper region to a good approximation

    Analysis and Testing of the FBA-11 Force [Balance] Accelerometer

    Get PDF
    The FBA-11 is a feedback-controlled accelerometer widely used to measure and record accelerations arising from earthquakes. It has found application both for structural response and for ground motion studies. The design intent of the FBA-11 was to provide electronic control of the natural frequency, damping, and output voltage. Included in this paper are (1) a circuit analysis yielding the complete closed-loop transfer function, and (2) the corroborative test results from shake table evaluations. The transfer function can be used to correct recorded accelerations for instrument response

    METALLOGRAPHIC EXAMINATION OF ORNL NO. 1, SHE NO. 2

    Full text link
    Small Heat Exchanger ORNL No. I, type SHE No. 2, was removed from test stand B after 2071 hours of operation; 1041 hours were under 4 T conditions. The heat exchanger contatned 20 Inconel tubes having an outside diameter of 0.25 in. and a wall thickness of 0.025 in. The outside of these tubes was exposed to the fluoride mixture NaF contained NaK (44% Na--56% K). During o degradation t T conditions, the fluoride temperature entering the heat exchanger was 1310 tained F and on leaving was 1235 tained F. The temperature of the NaK entering the heat exchanger was 1050 tained F and at the exit was 1290 tained F. During isothermal operation, the temperature of both the NaK and fluoride circuits was 1300 tained F. Thirtysix termperature transitions from isothermal to o degradation t T conditions were made during the course of operation. An examination of the resistance heater used in conjunction with this heat exchanger also was made: the results are reported. (auth

    Genetic relationships between sex-specific traits in beef cattle: Mature weight, weight adjusted for body condition score, height and body condition score of cows, and carcass traits of their steer relatives

    Get PDF
    Data from the first four cycles of the Germplasm Evaluation Program at the U.S. Meat Animal Research Center (USMARC) were used to investigate genetic relationships between mature weight (MW, n = 37,710), mature weight adjusted for body condition score (AMW, n = 37,676), mature height (HT, n = 37,123), and BCS (n = 37,676) from 4- to 8-yr old cows (n = 1,800) and carcass traits (n = 4,027) measured on their crossbred paternal half-sib steers. Covariance components among traits were estimated using REML. Carcass traits were adjusted for age at slaughter. Estimates of heritability for hot carcass weight (HCWT); percentage of retail product; percentage of fat; percentage of bone; longissimus muscle area; fat thickness adjusted visually; estimated kidney, pelvic, and heart fat percentage; marbling score; Warner-Bratzler shear force; and taste panel tenderness measured on steers were moderate to high (0.26 to 0.65), suggesting that selection for carcass and meat traits could be effective. Estimates of heritability for taste panel flavor and taste panel juiciness were low and negligible (0.05 and 0.01, respectively). Estimates of heritability from cow data over all ages and seasons were high for MW, AMW, and HT (0.52, 0.57, 0.71; respectively) and relatively low for BCS (0.16). Pair-wise analyses for each female mature trait with each carcass trait were done with bivariate animal models. Estimates of genetic correlations between cow mature size and carcass composition or meat quality traits, with the exception of HCWT, were relatively low. Selection for cow mature size (weight and/or height) could be effective and would not be expected to result in much, if any, correlated changes in carcass and meat composition traits. However, genetic correlations of cow traits, with the possible exception of BCS, with HCWT may be too large to ignore. Selection for steers with greater HCWT would lead to larger cows

    Expression of Epstein–Barr Virus–Encoded Small RNA (by the EBER-1 Gene) in Liver Specimens from Transplant Recipients with Post-Transplantation Lymphoproliferative Disease

    Get PDF
    Epstein-Barr virus (EBV)—associated post-transplantation lymphoproliferative disease (PTLD) develops in 1 to 10 percent of transplant recipients, in whom it can be treated by a reduction in the level of immunosuppression. We postulated that the tissue expression of the small RNA transcribed by the EBER-1 gene during latent EBV infection would identify patients at risk for PTLD. We studied EBER-1 gene expression in liver specimens obtained from 24 patients 2 days to 22 months before the development of PTLD, using in situ hybridization with an oligonucleotide probe. Control specimens were obtained from 20 recipients of allografts with signs of injury due to organ retrieval, acute graft rejection, or viral hepatitis in whom PTLD had not developed 9 to 71 months after the biopsy. Of the 24 patients with PTLD, 17 (71 percent) had specimens in which 1 to 40 percent of mononuclear cells were positive for the EBER-1 gene. In addition, 10 of these 17 patients (59 percent) had specimens with histopathological changes suggestive of EBV hepatitis. In every case, EBER-1—positive cells were found within the lymphoproliferative lesions identified at autopsy. Only 2 of the 20 controls (10 percent) had specimens with EBER-1—positive cells (P<0.001), and such cells were rare. EBER-1 gene expression in liver tissue precedes the occurrence of clinical and histologic PTLD. The possibility of identifying patients at risk by the method we describe here and preventing the occurrence of PTLD by a timely reduction of immunosuppression needs to be addressed by future prospective studies. (N Engl J Med 1992;327:1710–4.), POST-TRANSPLANTATION lymphoproliferative disease (PTLD), either polyclonal or monoclonal, complicates the clinical course of 1 to 10 percent of organ-transplant recipients.123 Immunohistochemical studies have demonstrated that the lymphoid cells within the lesions of PTLD almost invariably contain Epstein–Barr virus (EBV), primarily in a state of latent infection.4,5 The EBER-1 gene is expressed early during latent EBV infection and codes for a small messenger RNA (mRNA) expressed at up to 107 copies per cell.6 We and others have previously demonstrated the value of the detection of EBER-1 RNA for identifying EBV-infected cells in formalin-fixed paraffin-embedded tissues.7,8 In the current investigation, we used… © 1992, Massachusetts Medical Society. All rights reserved
    • …
    corecore