Two-stage, low noise advanced technology fan. 4: Aerodynamic final report

A two-stage research fan was tested to provide technology for designing a turbofan engine for an advanced, long range commercial transport having a cruise Mach number of 0.85 -0.9 and a noise level 20 EPNdB below current requirements. The fan design tip speed was 365.8m/sec (1200ft/sec);the hub/tip ratio was 0.4; the design pressure ratio was 1.9; and the design specific flow was 209.2 kg/sec/sq m(42.85lbm/sec/sq ft). Two fan-versions were tested: a baseline configuration, and an acoustically treated configuration with a sonic inlet device. The baseline version was tested with uniform inlet flow and with tip-radial and hub-radial inlet flow distortions. The baseline fan with uniform inlet flow attained an efficiency of 86.4% at design speed, but the stall margin was low. Tip-radial distortion increased stall margin 4 percentage points at design speed and reduced peak efficiency one percentage point. Hub-radial distortion decreased stall margin 4 percentage points at all speeds and reduced peak efficiency at design speed 8 percentage points. At design speed, the sonic inlet in the cruise position reduced stall margin one percentage point and efficiency 1.5 to 4.5 percentage points. The sonic inlet in the approach position reduced stall margin 2 percentage points

Irish Manufacturing Industry - Recent Wage, Price and Productivity Developments. Quarterly Economic Commentary, December 1982

Economic theory suggests that increases in money wages paid by firms greater than increases in output prices will lead to a fall in employment if there is not compensating productivity growth or flexibility of profit margins. The main aims of this paper are to consider, firstly, developments in the cost structure of Irish manufacturing industry if only the basic terms of the National Wage Agreements had been paid and secondly, to consider actual developments in the cost structure. To the extent that our traded goods are not perfect substitutes for traded goods elsewhere in the world economy we can influence the world price of Irish traded goods, so that the more our goods deviate from the "perfect substitutes" position the less the effect on output and employment of any adverse cost developments. In this paper the influence of cost increases on output prices is not considered; rather it is thought that the primary effect of these influences will be on output rather· than price so that the "price taker" model is being implicitly assumed. Section · 1 of the paper outlines some relevant theoretical considerations which are not highlighted in many treatments of the model. This framework is then used in Section 2 to consider the developments of industry labour costs under the basic terms of the National Wage Agreements since the end of 1975. Section 3 contrasts the proposals under these wage agreements with actual developments using earnings data

Experimental evaluation of transonic stators, data and performance report, multiple- circular-arc stator A

Transonic stator with multiple circular arc airfoils and minimum curvature tested over range of flow angles and velocities - stator

Two-stage fan. 3: Data and performance with rotor tip casing treatment, uniform and distorted inlet flows

A two stage fan with a 1st-stage rotor design tip speed of 1450 ft/sec, a design pressure ratio of 2.8, and corrected flow of 184.2 lbm/sec was tested with axial skewed slots in the casings over the tips of both rotors. The variable stagger stators were set in the nominal positions. Casing treatment improved stall margin by nine percentage points at 70 percent speed but decreased stall margin, efficiency, and flow by small amounts at design speed. Treatment improved first stage performance at low speed only and decreased second stage performance at all operating conditions. Casing treatment did not affect the stall line with tip radially distorted flow but improved stall margin with circumferentially distorted flow. Casing treatment increased the attenuation for both types of inlet flow distortion

An Econometric Model of Non-Agricultural Stock Changes. Quarterly Economic Commentary Special Article, December 1977

Macroeconometric models pay particular attention to the equations dealing with the major components of aggregate demand, such as consumption, investment and exports. In the Central Bank's econometric model [l], investment is broken down into three components: residential investment, non-residential investment and stockbuilding. While stockbuilding is a relatively small proportion of aggregate demand, it is a volatile magnitude and has traditionally been accorded an important place in the study of economic fluctuations. This note is devoted to a discussion of the stockbuilding equation. The following sections deal with the models tested, the empirical results and the conclusions. Data, sources and methods are given in the appendix

Three-Omega Thermal-Conductivity Measurements with Curved Heater Geometries

The three-omega method, a powerful technique to measure the thermal conductivity of nanometer-thick films and the interfaces between them, has historically employed straight conductive wires to act as both heaters and thermometers. When investigating stochastically prepared samples such as two-dimensional materials and nanomembranes, residue and excess material can make it difficult to fit the required millimeter-long straight wire on the sample surface. There are currently no available criteria for how diverting three-omega heater wires around obstacles affects the validity of the thermal measurement. In this Letter, we quantify the effect of wire curvature by performing three-omega experiments with a wide range of frequencies using both curved and straight heater geometries on SiO$_2$/Si samples. When the heating wire is curved, we find that the measured Si substrate thermal conductivity changes by only 0.2%. Similarly, we find that wire curvature has no significant effect on the determination of the thermal resistance of a $\sim$65 nm SiO$_2$ layer, even for the sharpest corners considered here, for which the largest measured ratio of the thermal penetration depth of the applied thermal wave to radius of curvature of the heating wire is 4.3. This result provides useful design criteria for three-omega experiments by setting a lower bound for the maximum ratio of thermal penetration depth to wire radius of curvature.Comment: 4 pages, 3 figure

Intensity enhancement of O VI ultraviolet emission lines in solar spectra due to opacity

Opacity is a property of many plasmas, and it is normally expected that if an emission line in a plasma becomes optically thick, its intensity ratio to that of another transition that remains optically thin should decrease. However, radiative transfer calculations undertaken both by ourselves and others predict that under certain conditions the intensity ratio of an optically thick to thin line can show an increase over the optically thin value, indicating an enhancement in the former. These conditions include the geometry of the emitting plasma and its orientation to the observer. A similar effect can take place between lines of differing optical depth. Previous observational studies have focused on stellar point sources, and here we investigate the spatially-resolved solar atmosphere using measurements of the I(1032 A)/I(1038 A) intensity ratio of O VI in several regions obtained with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument on board the Solar and Heliospheric Observatory (SoHO) satellite. We find several I(1032 A)/I(1038 A) ratios observed on the disk to be significantly larger than the optically thin value of 2.0, providing the first detection (to our knowledge) of intensity enhancement in the ratio arising from opacity effects in the solar atmosphere. Agreement between observation and theory is excellent, and confirms that the O VI emission originates from a slab-like geometry in the solar atmosphere, rather than from cylindrical structures.Comment: 17 pages, 4 figures, ApJ Letters, in pres

Two-stage fan. 4: Performance data for stator setting angle optimization

Stator setting angle optimization tests were conducted on a two-stage fan to improve efficiency at overspeed, stall margin at design speed, and both efficiency and stall margin at partspeed. The fan has a design pressure ratio of 2.8, a flow rate of 184.2 lb/sec (83.55 kg/sec) and a 1st-stage rotor tip speed of 1450 ft/sec (441.96 in/sec). Performance was obtained at 70,100, and 105 percent of design speed with different combinations of 1st-stage and 2nd-stage stator settings. One combination of settings, other than design, was common to all three speeds. At design speed, a 2.0 percentage point increase in stall margin was obtained at the expense of a 1.3 percentage point efficiency decrease. At 105 percent speed, efficiency was improved by 1.8 percentage points but stall margin decreased 4.7 percentage points. At 70 percent speed, no change in stall margin or operating line efficiency was obtained with stator resets although considerable speed-flow requlation occurred

Inter-Industry Differences in Male Percentage Unemployment Compensation - A Cross Section Analysis for Irish Manufacturing Industry. Quarterly Economic Commentary Special Article, November 1976

It is widely accepted that unemployment rates vary substantially amongst industrial sectors in Ireland. However, it does not appear to be equally recognised that there are substantial inter-industry differences in the percentage of net earnings which an unemployed person receives from Unemployment and Pay-Related Benefits. These differences are accentuated by the non-uniformity of the dependency structure of the labour force in different industries. This paper, therefore, comprises two parts. Part 1 is methodological and consists of an attempt to compute, under fairly restrictive assumptions, for each of 36 manufacturing industries, the proportion of net earnings obtained from unemployment compensation. This is done for persons of differing dependency status. These proportions are then weighted by the dependency distribution of the unemployed in each industry in order to obtain a representative percentage compensation figure for each of the 36 industries. Some space is devoted to an examination of these results. In Part 2 an attempt is made to explore the hypothesis that levels of unemployment compensation may be an important factor in explaining the extent and duration of registered unemployment

Optimization of double pulse pumping for Ni-like Sm x-ray lasers

We report a systematic study of double pulse pumping of the Ni-like Sm x-ray laser at 73 Angstrom, currently the shortest wavelength saturated x-ray laser. It is found that the Sm x-ray laser output can change by orders of magnitude when the intensity ratio of the pumping pulses and their relative delay are varied. Optimum pumping conditions are found and interpreted in terms of a simple model. (C) 1999 American Institute of Physics. [S0021-8979(99)07102-9]