Effect of forward motion on engine noise

Methods used to determine a procedure for correcting static engine data for the effects of forward motion are described. Data were analyzed from airplane flyover and static-engine tests with a JT8D-109 low-bypass-ratio turbofan engine installed on a DC-9-30, with a CF6-6D high-bypass-ratio turbofan engine installed on a DC-10-10, and with a JT9D-59A high-bypass-ratio turbofan engine installed on a DC-10-40. The observed differences between the static and the flyover data bases are discussed in terms of noise generation, convective amplification, atmospheric propagation, and engine installation. The results indicate that each noise source must be adjusted separately for forward-motion and installation effects and then projected to flight conditions as a function of source-path angle, directivity angle, and acoustic range relative to the microphones on the ground

Women Superintendents In Illinois: Gender Barriers and Challenges

Women face unique challenges as superintendents. This study determined barri- ers women face as superintendents and elicited reasons why these women would consider leaving the superintendent\u27s position. Thirty-nine PreK-12 women su- perintendents in Illinois participated in a web-based survey in January 2008. Survey items included information regarding characteristics, pathways to the superintendency, personal barriers, professional barriers, and factors that would cause women to consider leaving the superintendency. Respondents identified familial responsibilities, gender discrimination, employment opportunities, and self-confidence as major barriers. Factors that would cause women superinten- dents to leave their position included employment opportunities, familial re- sponsibilities, and peer support. Six women were also personally interviewed to clarify survey responses and to gain greater insights regarding the barriers. The women indicated that they had experienced barriers related to gender discrimi- nation and familial responsibilities. These barriers did not contribute to the su- perintendents leaving their current positions. Their reasons for seeking new positions would be to pursue opportunities that would enhance their profes- sional experiences or improve their compensation

Peanut Seed Treatment Tests in Texas.

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The structure, energy, and electronic states of vacancies in Ge nanocrystals

The atomic structure, energy of formation, and electronic states of vacancies in H-passivated Ge nanocrystals are studied by density functional theory (DFT) methods. The competition between quantum self-purification and the free surface relaxations is investigated. The free surfaces of crystals smaller than 2 nm distort the Jahn-Teller relaxation and enhance the reconstruction bonds. This increases the energy splitting of the quantum states and reduces the energy of formation to as low as 1 eV per defect in the smallest nanocrystals. In crystals larger than 2 nm the observed symmetry of the Jahn-Teller distortion matches the symmetry expected for bulk Ge crystals. Near the nanocrystal's surface the vacancy is found to have an energy of formation no larger than 0.5 to 1.4 eV per defect, but a vacancy more than 0.7 nm inside the surface has an energy of formation that is the same as in bulk Ge. No evidence of the self-purification effect is observed; the dominant effect is the free surface relaxations, which allow for the enhanced reconstruction. From the evidence in this paper, it is predicted that for moderate sized Ge nanocrystals a vacancy inside the crystal will behave bulk-like and not interact strongly with the surface, except when it is within 0.7 nm of the surface.Comment: In Press at Phys. Rev.

Bone Tissue Engineering: Scalability and Optimization of Densified Collagen-Fibril Bone Graft Substitute Materials

Over 240 million people missing teeth worldwide experience lingering problems such as difficulty speaking and eating, undesirable aesthetics, and resorption of bone supporting neighboring teeth. The gold standard of treatment utilizes grafts to attach a function-restoring implant to supporting bone. Current graft materials suffer from problems including autologous donor site morbidity, long resorption time, incomplete integration with the maxillae or mandible, and structural weakness. Patient-specific, cellularized bone grafts may be a solution to these issues by accelerating and improving the quality of regenerated bone. Recently, encapsulation of mesenchymal stem cells within self-assembling type I collagen oligomer matrices has been shown to support rapid mineralization of small-scale bone constructs (cylinders with diameter and height of 6mm and 1mm, respectively) in vitro. However, this method’s volume and geometric constraints for nutrient transport and cell viability are still unknown. In this study, the effects of construct size and medium formulation on mineralization were investigated using conventional static culture methods. To create constructs, human adipose stem cells (hASCs) were embedded in oligomer matrices, allowed to polymerize, and compressed to final cell and fibril densities of 3x107 cells/mL and 50 mg/mL, respectively. Varying construct sizes (maximum diameter and thickness of 11 mm and 0.81 mm) were cultured for 1 week in growth medium or osteogenic medium with varying calcium concentrations. Alizarin red staining was used to detect calcium deposits indicative of cell-induced mineralization. Preliminary data suggests that culture in osteogenic medium supplemented with both 8 mM and 16 mM calcium may induce rapid, uniform mineralization across all sizes tested, and 16 mM calcium supplementation induces greater mineralization. However, additional validation by direct measurement of cell viability and osteogenic differentiation will be needed to better compare bone regeneration as a function of scale

LAGEOS-type Satellites in Critical Supplementary Orbit Configuration and the Lense-Thirring Effect Detection

In this paper we analyze quantitatively the concept of LAGEOS--type satellites in critical supplementary orbit configuration (CSOC) which has proven capable of yielding various observables for many tests of General Relativity in the terrestrial gravitational field, with particular emphasis on the measurement of the Lense--Thirring effect.Comment: LaTex2e, 20 pages, 7 Tables, 6 Figures. Changes in Introduction, Conclusions, reference added, accepted for publication in Classical and Quantum Gravit

Hubble flow variance and the cosmic rest frame

We characterize the radial and angular variance of the Hubble flow in the COMPOSITE sample of 4534 galaxies, on scales in which much of the flow is in the nonlinear regime. With no cosmological assumptions other than the existence of a suitably averaged linear Hubble law, we find with decisive Bayesian evidence (ln B >> 5) that the Hubble constant averaged in independent spherical radial shells is closer to its asymptotic value when referred to the rest frame of the Local Group, rather than the standard rest frame of the Cosmic Microwave Background. An exception occurs for radial shells in the range 40/h-60/h Mpc. Angular averages reveal a dipole structure in the Hubble flow, whose amplitude changes markedly over the range 32/h-62/h Mpc. Whereas the LG frame dipole is initially constant and then decreases significantly, the CMB frame dipole initially decreases but then increases. The map of angular Hubble flow variation in the LG rest frame is found to coincide with that of the residual CMB temperature dipole, with correlation coefficient -0.92. These results are difficult to reconcile with the standard kinematic interpretation of the motion of the Local Group in response to the clustering dipole, but are consistent with a foreground non-kinematic anisotropy in the distance-redshift relation of 0.5% on scales up to 65/h Mpc. Effectively, the differential expansion of space produced by nearby nonlinear structures of local voids and denser walls and filaments cannot be reduced to a local boost. This hypothesis suggests a reinterpretation of bulk flows, which may potentially impact on calibration of supernovae distances, anomalies associated with large angles in the CMB anisotropy spectrum, and the dark flow inferred from the kinematic Sunyaev-Zel'dovich effect. It is consistent with recent studies that find evidence for a non-kinematic dipole in the distribution of distant radio sources.Comment: 37 pages, 9 tables, 13 figures; v2 adds extensive new analysis (including additional subsections, tables, figures); v3 adds a Monte Carlo analysis (with additional table, figure) which further tightens the statistical robustness of the dipole results; v4 adds further clarifications, small corrections, references and discussion of Planck satellite results; v5 typos fixed, matches published versio

Efficacy of a self-help manual in increasing resilience in carers of adults with depression in Thailand

Caring for a person with a mental illness can have adverse effects on caregivers; however, little is known about how best to help such caregivers. The aim of the present study was to examine the efficacy of a cognitive behaviour therapy-guided self-help manual in increasing resilience in caregivers of individuals with depression, in comparison to caregivers who receive routine support only. A randomized, controlled trial was conducted, following CONSORT guidelines, with 54 caregivers allocated to parallel intervention (self-help manual) (n = 27) or control (standard support) (n = 27) groups. Resilience was assessed at baseline, post-test (week 8), and follow up (week 12). Intention-to-treat analyses were undertaken. Repeated-measures ANOVA indicated a significant difference in resilience scores between the three time points, showing a large effect. Pairwise comparisons between intervention and control groups indicated resilience to be significantly different between baseline and post-test, and between baseline and follow up, but not between post-test and follow up. Overall, the intervention group showed a slightly greater increase in resilience over time than the control group; however, the time–group interaction was not significant. Guided self-help is helpful in improving caregivers’ resilience and could be used as an adjunct to the limited support provided to carers by mental health nurses and other clinicians

Ambipolar charge injection and transport in a single pentacene monolayer island

Electrons and holes are locally injected in a single pentacene monolayer island. The two-dimensional distribution and concentration of the injected carriers are measured by electrical force microscopy. In crystalline monolayer islands, both carriers are delocalized over the whole island. On disordered monolayer, carriers stay localized at their injection point. These results provide insight into the electronic properties, at the nanometer scale, of organic monolayers governing performances of organic transistors and molecular devices.Comment: To be published in Nano Letter