Low-speed wind-tunnel investigation of the flight dynamic characteristics of an advanced turboprop business/commuter aircraft configuration

An investigation was conducted to determine the low-speed flight dynamic behavior of a representative advanced turboprop business/commuter aircraft concept. Free-flight tests were conducted in the NASA Langley Research Center's 30- by 60-Foot Tunnel. In support of the free-flight tests, conventional static, dynamic, and free-to-roll oscillation tests were performed. Tests were intended to explore normal operating and post stall flight conditions, and conditions simulating the loss of power in one engine

High School Graduation and Dropout Rates in Nevada

The causes and consequences of high school dropout rates are multifaceted and of great importance to society, and that is why this problem has been the subject of close scrutiny by educators, researchers, administrators, politicians and laypersons. Experts do not always agree on the nature of this social problem, but they have pinpointed its economic and social costs, identified key risk factors, and outlined most promising policy options for improving high school graduation rates in our society

Registration of retinal images from Public Health by minimising an error between vessels using an affine model with radial distortions

In order to estimate a registration model of eye fundus images made of an affinity and two radial distortions, we introduce an estimation criterion based on an error between the vessels. In [1], we estimated this model by minimising the error between characteristics points. In this paper, the detected vessels are selected using the circle and ellipse equations of the overlap area boundaries deduced from our model. Our method successfully registers 96 % of the 271 pairs in a Public Health dataset acquired mostly with different cameras. This is better than our previous method [1] and better than three other state-of-the-art methods. On a publicly available dataset, ours still better register the images than the reference method

Social learning about environmental innovations: experimental analysis of adoption timing

This is the final version of the article. Available from Now Publishers via the DOI in this record.We conduct laboratory experiments to investigate how private and public information affect the selection of an environmental innovation and the timing of its adoption. The results reveal behavioral patterns underlying the “energyefficiency gap” in which consumers and firms delay adoption of cost-effective energy and environmental innovations. Our subjects choose between competing innovations with freedom to select the timing of their adoption, relying on private signals and possibly on observation of their peers' actions. When deciding whether to make an irreversible choice between a safe and a risky technology, roughly half of subjects delay adoption beyond the time prescribed by equilibrium behavior — pointing to a possible behavioral anomaly. When they do adopt, subjects give proportionately more weight to their private signals than to their peers' actions, implying that they do not ‘herd’ on the actions of their peers. Nevertheless, when subjects observe their peers' decisions, they accelerate the timing of their adoptions, but do not necessarily imitate their peers. This occurs even when payoffs are statistically independent as though observing prior adoptions exerts “peer pressure” on the subjects to act. The experimental results suggest that rapid dissemination of information of peer actions can speed up diffusion of innovations that save energy and protect the environment, and improve selection from among competing technologies.Financial support for this research was provided by France Telecom Research & Development, LLC

A microgravity isolation mount

The design and preliminary testing of a system for isolating microgravity sensitive payloads from spacecraft vibrational and impulsive disturbances is discussed. The Microgravity Isolation Mount (MGIM) concept consists of a platform which floats almost freely within a limited volume inside the spacecraft, but which is constrained to follow the spacecraft in the long term by means of very weak springs. The springs are realized magnetically and form part of a six degree of freedom active magnetic suspension system. The latter operates without any physical contact between the spacecraft and the platform itself. Power and data transfer is also performed by contactless means. Specifications are given for the expected level of input disturbances and the tolerable level of platform acceleration. The structural configuration of the mount is discussed and the design of the principal elements, i.e., actuators, sensors, control loops and power/data transfer devices are described. Finally, the construction of a hardware model that is being used to verify the predicted performance of the MGIM is described

Evidence for a Molecular Cloud Origin for Gamma-Ray Bursts: Implications for the Nature of Star Formation in the Universe

It appears that the majority of rapidly-, well-localized gamma-ray bursts with undetected, or dark, optical afterglows, or `dark bursts' for short, occur in clouds of size R > 10L_{49}^{1/2} pc and mass M > 3x10^5L_{49} M_{sun}, where L is the isotropic-equivalent peak luminosity of the optical flash. We show that clouds of this size and mass cannot be modeled as a gas that is bound by pressure equilibrium with a warm or hot phase of the interstellar medium (i.e., a diffuse cloud): Such a cloud would be unstable to gravitational collapse, resulting in the collapse and fragmentation of the cloud until a burst of star formation re-establishes pressure equilibrium within the fragments, and the fragments are bound by self-gravity (i.e., a molecular cloud). Consequently, dark bursts probably occur in molecular clouds, in which case dark bursts are probably a byproduct of this burst of star formation if the molecular cloud formed recently, and/or the result of lingering or latter generation star formation if the molecular cloud formed some time ago. We then show that if bursts occur in Galactic-like molecular clouds, the column densities of which might be universal, the number of dark bursts can be comparable to the number of bursts with detected optical afterglows: This is what is observed, which suggests that the bursts with detected optical afterglows might also occur in molecular clouds. We confirm this by modeling and constraining the distribution of column densities, measured from absorption of the X-ray afterglow, of the bursts with detected optical afterglows: We find that this distribution is consistent with the expectation for bursts that occur in molecular clouds, and is not consistent with the expectation for bursts that occur in diffuse clouds. More...Comment: Accepted to The Astrophysical Journal, 22 pages, 6 figures, LaTe

Suprathermal plasma observed on STS-3 Mission by plasma diagnostics package

Artificially produced electron beams were used extensively during the past decade as a means of probing the magnetosphere, and more recently as a means of actively controlling spacecraft potential. Experimentation in these areas has proven valuable, yet at times confusing, due to the interaction of the electron beam with the ambient plasma. The OSS-1/STS-3 Mission in March 1982 provided a unique opportunity to study beam-plasma interactions at an altitude of 240 km. On board for this mission was a Fast Pulse Electron Generator (FPEG). Measurements made by the Plasma Diagnostics Package (PDP) while extended on the Orbiter RMS show modifications of the ion and electron energy distributions during electron beam injection. Observations made by charged particle detectors are discussed and related to measurements of Orbiter potential. Several of the PDP instruments, the joint PDP/FPEG experiment, and observations made during electron beam injection are described

Cost-effectiveness of a potential vaccine for Coccidioides immitis.

Coccidioidomycosis, a systemic fungal infection, affects Americans living in the Southwest. We evaluated the cost- effectiveness of a potential vaccine against Coccidioides immitis. Using a decision model we developed, we estimate that among children, vaccination would saved 1.9 quality-adjusted life days (QALD) and $33 per person. Among adults, screening followed by vaccination would save 0.5 QALD per person and cost$62,000 per quality adjusted life year gained over no vaccination. If the birth cohort in highly endemic counties of California and Arizona were immunized in 2001, 11 deaths would be averted and $3 million would be saved (in net present value) over the lifetime of these infants. Vaccination of adults to prevent disseminated coccidioidomycosis would provide a modest health benefit similar in magnitude to other vaccines but would increase net expenditures. Vaccination of children in highly endemic regions would provide a larger health benefit and would reduce total health care expenditures

Constraining the rate of oceanic deoxygenation leading up to a Cretaceous Oceanic Anoxic Event (OAE-2: ~94 Ma)

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Science Advances 3 (2017): e1701020, doi:10.1126/sciadv.1701020.The rates of marine deoxygenation leading to Cretaceous Oceanic Anoxic Events are poorly recognized and constrained. If increases in primary productivity are the primary driver of these episodes, progressive oxygen loss from global waters should predate enhanced carbon burial in underlying sediments—the diagnostic Oceanic Anoxic Event relic. Thallium isotope analysis of organic-rich black shales from Demerara Rise across Oceanic Anoxic Event 2 reveals evidence of expanded sediment-water interface deoxygenation ~43 ± 11 thousand years before the globally recognized carbon cycle perturbation. This evidence for rapid oxygen loss leading to an extreme ancient climatic event has timely implications for the modern ocean, which is already experiencing large-scale deoxygenation.We would like to acknowledge support from the NSF grant OCE 1434785 (to J.D.O. and S.G.N.), the NASA Exobiology grant NNX16AJ60G (to J.D.O. and S.G.N.), a WHOI Summer Student Fellowship (to C.M.O.), and an Agouron Postdoctoral Fellowship (to J.D.O.). This material is based on work supported by the NSF Graduate Research Fellowship Program under grant no. 026257-001

Developing IFC for infrastructure: A case study of three highway entities

Modern cities pay particular attention to upscale their infrastructure systems in order to improve the every-day life of their citizens and lead the way towards a more sustainable environment. As part of this, they invest extensive funds in large infrastructure projects which are challenging to deliver as they require an e efficient communication among different professions, in order to share information efficiently throughout the lifecycle of the project, thus highlighting the importance of standardization to maintain consistency and integrity during data exchange. Building Information Modelling (BIM) aims to facilitate the above-mentioned requirements by describing the life-cycle of the project and Industry Foundation Classes (IFC) is the Standard for BIM that enables an efficient storage, management, exchange and visualization of information. However, there are two important challenges that need to be addressed: (i) IFC focuses particularly on buildings and provides limited support for infrastructure elements and (ii) the information exchange aims to describe mostly the construction phase; highlighting the lack of classes that refer to the operation and maintenance phase. Within this context, this paper proposes the extension of Industry Foundation Classes (IFC) for Asset Management in Infrastructure. A method is developed based on a case study of three highway entities: (i) retaining wall, (ii) gantry and (iii) bridge and a conceptual extension is presented. The results are further discussed and recommendations regarding future research fields are proposed