Evaluation of flow quality in two large NASA wind tunnels at transonic speeds

Wind tunnel testing of low drag airfoils and basic transition studies at transonic speeds are designed to provide high quality aerodynamic data at high Reynolds numbers. This requires that the flow quality in facilities used for such research be excellent. To obtain a better understanding of the characteristics of facility disturbances and identification of their sources for possible facility modification, detailed flow quality measurements were made in two prospective NASA wind tunnels. Experimental results are presented of an extensive and systematic flow quality study of the settling chamber, test section, and diffuser in the Langley 8 foot transonic pressure tunnel and the Ames 12 foot pressure wind tunnel. Results indicate that the free stream velocity and pressure fluctuation levels in both facilities are low at subsonic speeds and are so high as to make it difficult to conduct meaningful boundary layer control and transition studies at transonic speeds

Design and preliminary test results at Mach 5 of an axisymmetric slotted sound shield

The basic theory and sound attenuation mechanisms, the design procedures, and preliminary experimental results are presented for a small axisymmetric sound shield for supersonic wind tunnels. The shield consists of an array of small diameter rods aligned nearly parallel to the entrance flow with small gaps between the rods for boundary layer suction. Results show that at the lowest test Reynolds number (based on rod diameter) of 52,000 the noise shield reduced the test section noise by about 60 percent ( or 8 db attenuation) but no attenuation was measured for the higher range of test reynolds numbers from 73,000 to 190,000. These results are below expectations based on data reported elsewhere on a flat sound shield model. The smaller attenuation from the present tests is attributed to insufficient suction at the gaps to prevent feedback of vacuum manifold noise into the shielded test flow and to insufficient suction to prevent transition of the rod boundary layers to turbulent flow at the higher Reynolds numbers. Schlieren photographs of the flow are shown

Flow diagnostics and visualization in wind tunnels and flight

The Langley Research Center has a concentrated and directed effort under way to develop both conventional and non-intrusive diagnostic instrumentation. These instruments are being developed to operate over large Mach number, total temperature, and total pressure ranges. Efforts are being made to evaluate the measurements made by the various instruments to determine the most accurate and reliable instrument to be used under a given flow environment. Although only one flow visualization technique was described, there are many different types presently being used at Langley Research Center

Panamanian Grandmothers' Family Relationships and Adjustment to Having a Grandchild with a Disability

The purpose of this article was to explore the family relationships and role adjustment of grandmothers in the Republic of Panama who have a grandchild with special needs. Thirty Panamanian grandmothers of children with a disability were interviewed using a standardized format and non-directive probing. Categories of analysis were established only after the data was fully collected and reviewed. The results indicate that for most Panamanian grandmothers, their changes in family relationships are not dramatic when they have a grandchild with a disability; however, 25% clearly report a deteriorated relationship with their son-in-laws. They view their relationship with their grandchild with a disability to be one that provides a mixture of affection, love, acceptance and patience. In the area of role adjustment, they see a need to become more involved in areas that include assisting their grandchildren and/or her family with caregiving and household responsibilities, economic and medical support, or in areas related to school/academic, spiritual or recreational activities. With respect to emotional adjustment, Panamanian grandmothers of children with disabilities distinguish themselves from grandmothers in the United States, by experiencing reduced emotional stress and dwelling less on personal loss, grief, or role stigma. The implications are that there appear to be universal beliefs and adjustment factors that Panamanian grandmothers of grandchildren with disabilities experience. However, culture appears to have a genuine influence that results in subtle but unique differences from their U.S. counterparts.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Enduring Legacy? Charles Tilly and Durable Inequality

This article assesses Charles Tilly’s Durable Inequality and traces its influence. In writing Durable Inequality, Tilly sought to shift the research agenda of stratification scholars. But the book’s initial impact was disappointing. In recent years, however, its influence has grown, suggesting a more enduring legacy

Accounting for risk in valuing forest carbon offsets

<p>Abstract</p> <p>Background</p> <p>Forests can sequester carbon dioxide, thereby reducing atmospheric concentrations and slowing global warming. In the U.S., forest carbon stocks have increased as a result of regrowth following land abandonment and in-growth due to fire suppression, and they currently sequester approximately 10% of annual US emissions. This ecosystem service is recognized in greenhouse gas protocols and cap-and-trade mechanisms, yet forest carbon is valued equally regardless of forest type, an approach that fails to account for risk of carbon loss from disturbance.</p> <p>Results</p> <p>Here we show that incorporating wildfire risk reduces the value of forest carbon depending on the location and condition of the forest. There is a general trend of decreasing risk-scaled forest carbon value moving from the northern toward the southern continental U.S.</p> <p>Conclusion</p> <p>Because disturbance is a major ecological factor influencing long-term carbon storage and is often sensitive to human management, carbon trading mechanisms should account for the reduction in value associated with disturbance risk.</p

Working towards inclusive physical education in a primary school: ‘some days I just don’t get it right’

© 2018 Association for Physical Education Background: In Aotearoa New Zealand, as it is internationally, there is a desire to ensure physical education is inclusive of all students regardless of their abilities. Yet, medical discourses associated with disability continue to position students who are perceived as not having the capacity to participate fully in traditional physical education programmes as the teacher’s ‘helper’, ‘helped’, or ‘helpless’. As a result, these students may have negative experiences of physical education and this can impact on future involvement in movement-related activities within school and community settings. Methodology: Drawing on the data from a larger critical participatory action research project, we explore how one primary school teacher, Joel, attempted to work more inclusively within physical education. Specifically, we draw from personal journaling, student work and records of dialogical conversations to shed light on Joel’s experiences. Conclusion: Joel’s experience demonstrates that there is not one singular solution to inclusion within physical education and it is a combination of actions that support this process. In Joel’s case, this included becoming a reflexive practitioner, getting to know his students, being receptive as opposed to respective to difference in positive ways rather than seeing this as limiting, working imaginatively to reconsider what constitutes learning in physical education, and sharing ownership for curriculum design and learning with his students. Working in this way illustrates how a multi-layered approach can make a difference to how all the students in a class experience inclusion, including students positioned as disabled

The Relationship of Maternal Prepregnancy Body Mass Index and Pregnancy Weight Gain to Neurocognitive Function at Age 10 Years among Children Born Extremely Preterm

OBJECTIVE: To assess the association between maternal prepregnancy body mass index and adequacy of pregnancy weight gain in relation to neurocognitive function in school-aged children born extremely preterm. STUDY DESIGN: Study participants were 535 ten-year-old children enrolled previously in the prospective multicenter Extremely Low Gestational Age Newborns cohort study who were products of singleton pregnancies. Soon after delivery, mothers provided information about prepregnancy weight. Prepregnancy body mass index and adequacy of weight gain were characterized based on this information. Children underwent a neurocognitive evaluation at 10 years of age. RESULTS: Maternal prepregnancy obesity was associated with increased odds of a lower score for Differential Ability Scales-II Verbal IQ, for Developmental Neuropsychological Assessment-II measures of processing speed and visual fine motor control, and for Wechsler Individual Achievement Test-III Spelling. Children born to mothers who gained an excessive amount of weight were at increased odds of a low score on the Oral and Written Language Scales Oral Expression assessment. Conversely, children whose mother did not gain an adequate amount of weight were at increased odds of a lower score on the Oral and Written Language Scales Oral Expression and Wechsler Individual Achievement Test-III Word Reading assessments. CONCLUSION: In this cohort of infants born extremely preterm, maternal obesity was associated with poorer performance on some assessments of neurocognitive function. Our findings are consistent with the observational and experimental literature and suggest that opportunities may exist to mitigate risk through education and behavioral intervention before pregnancy

Labeling Preschoolers as Learning Disabled: A Cautionary Position

The purpose of this article is to explore the issues concerning the adaptation of school-based service delivery concepts for use in early childhood special education programs. The use of categorical labels for determining eligibility for preschool children is not required by law—and may be detrimental. The following concerns are discussed: (a) definitional issues in learning disabilities versus low achievement, (b) the dangers of labeling and low expectation sets, (c) repeated failure to demonstrate movement through a continuum of services (particularly to least restrictive environments), and (d) the efficacy of early intervention and school-based special services for those with mild or suspected developmental disabilities. Research is reviewed concerning definitional and assessment issues utilizing learning disabilities as a construct. Alternatives for describing the characteristics of young children who are significantly at risk or developmentally delayed are provided.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline