Turbine modeling technique to generate off-design performance data for both single and multistage axial-flow turbines

This technique is applicable to larger axial flow turbines which may or may not incorporate variable geometry in the first stage stator. A user specified option will also permit the calculation of design point cooling flow levels and the corresponding change in turbine efficiency. The modeling technique was incorporated into a time sharing computer program in order to facilitate its use. Because this report contains a description of the input output data, values of typical inputs, and example cases, it is suitable as a user's manual

Extended parametric representation of compressor fans and turbines. Volume 1: CMGEN user's manual

A modeling technique for fans, boosters, and compressors has been developed which will enable the user to obtain consistent and rapid off-design performance from design point input. The fans and compressors are assumed to be multi-stage machines incorporating front variable stators. The boosters are assumed to be fixed geometry machines. The modeling technique has been incorporated into time sharing program to facilitate its use. Because this report contains a description of the input output data, values of typical inputs, and examples cases, it is suitable as a user's manual. This report is the first of a three volume set describing the parametric representation of compressors, fans, and turbines. The titles of the three volumes are as follows: (1) Volume 1 CMGEN USER's Manual (Parametric Compressor Generator); (2) Volume 2 PART USER's Manual (parametric Turbine); (3) Volume 3 MODFAN USER's Manual (Parametric Modulating Flow Fan)

High-resolution digital surface characterization of the Rio Chama in New Mexico

Over the past eighty years, the Rio Chama, a major tributary of the Rio Grande in New Mexico, has been subject to significant disruption of historic hydrological flow regimes due to water use demands. In recent years, a multiagency management effort has been initiated to restore some measure of historic flow regimes in the 39.6 km congressionally designated Wild and Scenic stretch through the Rio Chama Canyon Wilderness. We collaborated with managers at the US Army Corps of Engineers to collect approximately 15,870 frames of 10cm resolution multispectral imagery of the 82 km stretch of the river between El Vado Dam and Abiquiu Dam, which includes the Wild and Scenic area. Through structure-from-motion and multi-view stereo processing, a 20cm resolution digital surface model (DSM) and 10cm orthomosaic were generated. This imagery will be used for a variety of research and management purposes, but here we present the results of an experiment examining the impact of oblique-angle imagery on vertical error rates in DSMs. Two DSMs were derived from a subset of 1,674 frames of the aerial imagery, one with nadir imagery only and one with an additional 187 frames of oblique imagery flown at a 10 degree angle relative to the horizon. We used vertical root mean square error of check points collected with RTK positioning to evaluate vertical accuracy of the DSMs

Vaporization of high-temperature potassium in forced convection at saturation temperatures of 1800 deg to 2100 deg F

Heat transfer and fluid flow during forced convection vaporization of high temperature potassiu

Alkali metals boiling and condensing investigations quarterly progress report no. 12, 1 apr. - 30 jun. 1965

Alkali metals boiling and condensing investigations of two-phase heat transfer and fluid flow for potassiu

Estimating Operational Validity Under Incidental Range Restriction: Some Important but Neglected Issues

Operational validities are important to personnel selection research because they estimate how well a predictor in practical use correlates with a criterion construct, if the criterion measure were purged of measurement error variance. Because range restriction on a predictor or predictor composite creates incidental range restriction on the criterion, existing methodologies offer limited information and guidance for estimating operational validities. Although these effects of range restriction and criterion unreliability could be corrected with existing equations in a sequential fashion, proper use of sequential correction equations is not always as straightforward as it appears. This research reviews the existing equations for correcting validities, outlines the appropriate method for correcting validity coefficients via sequential equations, and proposes a new equation that performs a combined correction for the effects of incidental range restriction and criterion unreliability

Estimating Operational Validity Under Incidental Range Restriction: Some Important but Neglected Issues

Operational validities are important to personnel selection research because they estimate how well a predictor in practical use correlates with a criterion construct, if the criterion measure were purged of measurement error variance. Because range restriction on a predictor or predictor composite creates incidental range restriction on the criterion, existing methodologies offer limited information and guidance for estimating operational validities. Although these effects of range restriction and criterion unreliability could be corrected with existing equations in a sequential fashion, proper use of sequential correction equations is not always as straightforward as it appears. This research reviews the existing equations for correcting validities, outlines the appropriate method for correcting validity coefficients via sequential equations, and proposes a new equation that performs a combined correction for the effects of incidental range restriction and criterion unreliability. Accessed 1,910 times on https://pareonline.net from August 06, 2017 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right

Development of a Fan for Future Space Suit Applications

NASA's next generation space suit system will place new demands on the fan used to circulate breathing gas through the ventilation loop of the portable life support system. Long duration missions with frequent extravehicular activities (EVAs), the requirement for significant increases in reliability and durability, and a mission profile that imposes strict limits on weight, volume and power create the basis for a set of requirements that demand more performance than is available from existing fan designs. This paper describes the development of a new fan to meet these needs. A centrifugal fan was designed with a normal operating speed of approximately 39,400 rpm to meet the ventilation flow requirements while also meeting the aggressive minimal packaging, weight and power requirements. The prototype fan also operates at 56,000 rpm to satisfy a second operating condition associated with a single fan providing ventilation flow to two spacesuits connected in series. This fan incorporates a novel nonmetallic "can" to keep the oxygen flow separate from the motor electronics, thus eliminating ignition potential. The nonmetallic can enables a small package size and low power consumption. To keep cost and schedule within project bounds a commercial motor controller was used. The fan design has been detailed and implemented using materials and approaches selected to address anticipated mission needs. Test data is presented to show how this fan performs relative to anticipated ventilation requirements for the EVA portable life support system. Additionally, data is presented to show tolerance to anticipated environmental factors such as acoustics, shock, and vibration. Recommendations for forward work to progress the technology readiness level and prepare the fan for the next EVA space suit system are also discussed

You’re Having Fun When Time Flies: The Hedonic Consequences of Subjective Time Progression

Seven studies tested the hypothesis that people use subjective time progression in hedonic evaluation. When people believe that time has passed unexpectedly quickly, they rate tasks as more engaging, noises as less irritating, and songs as more enjoyable. We propose that felt time distortion operates as a metacognitive cue that people implicitly attribute to their enjoyment of an experience (i.e., time flew, so the experience must have been fun). Consistent with this attribution account, the effects of felt time distortion on enjoyment ratings were moderated by the need for attribution, the strength of the “time flies” naive theory, and the presence of an alternative attribution. These findings suggest a previously unexplored process through which subjective time progression can influence the hedonic evaluation of experiences