Preliminary rotor wake measurements with a laser velocimeter

A laser velocimeter (LV) was used to determine rotor wake characteristics. The effect of various fuselage widths and rotor-fuselage spacings on time averaged and detailed time dependent rotor wake velocity characteristics was defined. Definition of time dependent velocity characteristics was attempted with the LV by associating a rotor azimuth position with each velocity measurement. Results were discouraging in that no apparent time dependent velocity characteristics could be discerned from the LV measurements. Since the LV is a relatively new instrument in the rotor wake measurement field, the cause of this lack of periodicity is as important as the basic research objectives. An attempt was made to identify the problem by simulated acquisition of LV-type data for a predicted rotor wake velocity time history. Power spectral density and autocorrelation function estimation techniques were used to substantiate the conclusion that the primary cause of the lack of time dependent velocity characteristics was the nonstationary flow condition generated by the periodic turbulence level that currently exists in the open throat configuration of the wind tunnel

Exhaust emissions reduction for intermittent combustion aircraft engines

Three concepts which, to an aircraft piston engine, provide reductions in exhaust emissions of hydrocarbons and carbon monoxide while simultaneously improving fuel economy. The three chosen concepts, (1) an improved fuel injection system, (2) an improved cooling cylinder head, and (3) exhaust air injection, when combined, show a synergistic relationship in achieving these goals. In addition, the benefits of variable ignition timing were explored and both dynamometer and flight testing of the final engine configuration were accomplished

Screening analysis and selection of emission reduction concepts for intermittent combustion aircraft engines

An analysis was conducted to screen, evaluate, and select three engine exhaust emission reduction concepts from a group of 14 candidate alternatives. A comprehensive literature search was conducted to survey the emission reduction technology state-of-the-art and establish contact with firms working on intermittent combustion engine development and pollution reduction problems. Concept development, advantages, disadvantages, and expected emission reduction responses are stated. A set of cost effectiveness criteria was developed, appraised for relative importance, and traded off against each concept so that its merit could be determined. A decision model was used to aid the evaluators in managing the criteria, making consistent judgements, calculating merit scores, and ranking the concepts. An Improved Fuel Injection System, Improved Cooling Combustion Chamber, and a Variable Timing Ignition System were recommended to NASA for approval and further concept development. An alternate concept, Air Injection, was also recommended

Good Citizen: Trustworthy

As stated in the beginning of chapter 5, each trait addressed in the specified chapter is titled with the traits, then in the chapter there are character behavior definitions followed by anecdotes about where this trait was witnessed. Or, there may be a story having the time when the person involved, personally, acted on this trait. Such is the case for this chapter with the two culminating internationally recognized person-of-good-character traits of being a good citizen, and being trustworthy. The contributors are all speaking reflectively about a time in their lives that was of such emotional significance that it is remembered from a few years to decades later. Each definition is followed by one or two examples presented anecdotally. The chapter ends with “Journal and/or Discussion Questions

Notes from the Field: Understanding Why Sibling Abuse Remains Under the Radar and Pathways to Outing

The identification of sibling abuse is imperative to the emotional well-being of the victim, the perpetrator, and the family system. Sibling abuse has been identified as the most common form of family violence (Button, Parker, & Gealt, 2008; Reid & Donovan, 1990). It occurs more frequently than parent-child abuse or spousal abuse (Graham-Bermann, Cutler, Litzenberger, & Schwartz, 1994), yet it remains largely unaddressed in the literature and subsequently under the radar of child welfare, social service providers, and mental health practitioners. Highlighted in this paper is the need for those working in the field of mental health and social service to detect sibling abuse and its significant and detrimental impact. The aim of this paper is to broaden awareness of sibling abuse through the distinction of sibling abuse from normative sibling relational behavior and consider factors which prevent sibling abuse from gaining attention. Pathways to expanding knowledge of sibling abuse and integrating a sibling abuse framework is proposed to arm educators, practitioners, and child welfare staff to take action

Laser velocimetry technique applied to the Langley 0.3 meter transonic cryogenic tunnel

A low power laser velocimeter operating in the forward scatter mode was used to measure free stream mean velocities in the Langley 0.3 Meter Transonic Cryogenic Tunnel. Velocity ranging from 51 to 235 m/s was measured. Measurements were obtained for a variety of nominal tunnel conditions: Mach numbers from 0.20 to 0.77, total temperatures from 100 to 250 K, and pressures from 101 to 152 kPa. Particles were not injected to augment the existing Mie scattering materials. Liquid nitrogen droplets were the existing liqht scattering material. Tunnel vibrations and thermal effects had no detrimental effects on the optical system

Children's construction task performance and spatial ability: controlling task complexity and predicting mathematics performance.

This paper presents a methodology to control construction task complexity and examined the relationships between construction performance and spatial and mathematical abilities in children. The study included three groups of children (N = 96); ages 7-8, 10-11, and 13-14 years. Each group constructed seven pre-specified objects. The study replicated and extended previous findings that indicated that the extent of component symmetry and variety, and the number of components for each object and available for selection, significantly predicted construction task difficulty. Results showed that this methodology is a valid and reliable technique for assessing and predicting construction play task difficulty. Furthermore, construction play performance predicted mathematical attainment independently of spatial ability