Evaluation of meteorological airborne Doppler radar

This paper will discuss the capabilities of airborne Doppler radar for atmospheric sciences research. The evaluation is based on airborne and ground based Doppler radar observations of convective storms. The capability of airborne Doppler radar to measure horizontal and vertical air motions is evaluated. Airborne Doppler radar is shown to be a viable tool for atmospheric sciences research

A study of model deflection measurement techniques applicable within the national transonic facility

Moire contouring, scanning interferometry, and holographic contouring were examined to determine their practicality and potential to meet performance requirements for a model deflection sensor. The system envisioned is to be nonintrusive, and is to be capable of mapping or contouring the surface of a 1-meter by 1-meter model with a resolution of 50 to 100 points. The available literature was surveyed, and computations and analyses were performed to establish specific performance requirements, as well as the capabilities and limitations of such a sensor within the geometry of the NTF section test section. Of the three systems examined, holographic contouring offers the most promise. Unlike Moire, it is not hampered by limited contour spacing and extraneous fringes. Its transverse resolution can far exceed the limited point sampling resolution of scanning heterodyne interferometry. The availability of the ruby laser as a high power, pulsed, multiple wavelength source makes such a system feasible within the NTF

Observation of the Cosmic Ray Electron- Positron Ratio from 100 Mev to 3 Bev in 1964

Balloon flight data on cosmic ray electron- positron ratio from 100 MeV to 3 Be

Extended dust emission and atomic hydrogen, a reservoir of diffuse H_2 in NGC 1068

We report on sensitive sub-mm imaging observations of the prototype Seyfert~2/starburst galaxy NGC 1068 at 850 $\mu$m and 450 $\mu$m using the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). We find clear evidence of dust emission associated with the extended HI component which together with the very faint $^{12}$CO J=1--0 emission give a gas-to-dust ratio of $\rm M_{\rm gas}/M_{\rm dust} \sim 70-150$. This contrasts with the larger ratio $\rm M_{\rm gas}/M_{\rm dust}\sim 330$ estimated within a galactocentric radius of $r\leq 1.36$ kpc, where the gas is mostly molecular and starburst activity occurs. The large gas-to-dust ratio found for the starburst region is attributed to a systematic overestimate of the molecular gas mass in starburst environments when the luminosity of the $^{12}$CO J=1--0 line and a standard galactic conversion factor is used. On the other hand sub-mm imaging proves to be a more powerful tool than conventional CO imaging for revealing the properties of the diffuse $\rm H_2$ that coexists with HI. This molecular gas phase is characterized by low densities ($\rm n(H_2)<10^3$ cm$^{-3}$), very faint emission from sub-thermally excited CO, and contains more mass than HI, namely $\rm M(H_2)/M(HI)\sim 5$.Comment: Accepted for publication in the Astrophysical Journal Letter

Mapping of Materials Stress with Ultrasonic Tomography

It is known that internal stress concentrations can give rise to microcracks which then grow when the structure is subjected to external forces. It has also been found that the velocity of sound is altered as it propagates through a region of stress. In this paper we discuss a technique called Computer Assisted Tomography (CAT) and describe an application that provides pictures of stress fields. We report the results of both simulated and experimental models used to evaluate the technique. We conclude that the CAT approach has great potential for locating and mapping residual stress in metals

Resolving velocity space dynamics in continuum gyrokinetics

Many plasmas of interest to the astrophysical and fusion communities are weakly collisional. In such plasmas, small scales can develop in the distribution of particle velocities, potentially affecting observable quantities such as turbulent fluxes. Consequently, it is necessary to monitor velocity space resolution in gyrokinetic simulations. In this paper, we present a set of computationally efficient diagnostics for measuring velocity space resolution in gyrokinetic simulations and apply them to a range of plasma physics phenomena using the continuum gyrokinetic code GS2. For the cases considered here, it is found that the use of a collisionality at or below experimental values allows for the resolution of plasma dynamics with relatively few velocity space grid points. Additionally, we describe implementation of an adaptive collision frequency which can be used to improve velocity space resolution in the collisionless regime, where results are expected to be independent of collision frequency.Comment: 20 pages, 11 figures, submitted to Phys. Plasma

High-spatial-resolution CN and CS observation of two regions of massive star formation

Molecular line CN, CS and mm continuum observations of two intermediate- to high-mass star-forming regions - IRAS20293+3952 and IRAS19410+2336 - obtained with the Plateau de Bure Interferometer at high spatial resolution reveal interesting characteristics of the gas and dust emission. In spite of the expectation that the CN and CS morphology might closely follow the dense gas traced by the dust continuum, both molecules avoid the most central cores. Comparing the relative line strengths of various CN hyperfine components, this appears not to be an opacity effect but to be due to chemical and physical effects. The CN data also indicate enhanced emission toward the different molecular outflows in the region. Regarding CS, avoiding the central cores can be due to high optical depth, but the data also show that the CS emission is nearly always associated with the outflows of the region. Therefore, neither CS nor CN appear well suited for dense gas and disk studies in these two sources, and we recommend the use of different molecules for future massive disk studies. An analysis of the 1 and 3mm continuum fluxes toward IRAS20293+3952 reveals that the dust opacity index beta is lower than the canonical value of 2. Tentatively, we identify a decreasing gradient of beta from the edge of the core to the core center. This could be due to increasing optical depth toward the core center and/or grain growth within the densest cores and potential central disks. We detect 3mm continuum emission toward the collimated outflow emanating from IRAS20293+3952. The spectral index of alpha ~ 0.8 in this region is consistent with standard models for collimated ionized winds.Comment: 5 pages, 2 tables, 9 figures, accepted for Ap

A Gulf United: Canada-U.S. Transboundary Marine Ecosystem-Based Governance In The Gulf Of Maine

In 1989, the Northeastern states of Maine, Massachusetts, and New Hampshire in the United States and the neighboring Canadian Provinces of New Brunswick and Nova Scotia embarked upon a new form of regional marine environmental cooperation when their governors and premiers adopted the Agreement on Conservation of the Marine Environment of the Gulf of Maine Between the Governments of the Bordering States and Provinces. By doing so, they gave birth to an informal regime for the Gulf of Maine (GoM) (i.e. the Gulf of Maine Council on the Marine Environment), which to date has withstood the test of time. GoM regime participants undertake transboundary cooperation on the basis of shared ecosystem goals and objectives, as well as through the implementation of quinquennial Action Plans. In doing so, regime participants have effectively cooperated on the basis of a generally informal framework consisting of soft principles, understandings, and processes reflecting their mutual expectations in the regime’s issue areas. The GoM regime has been the subject of several scholarly reviews in recent years. Chircop et al. noted that the GoM regime: may be viewed as novel in at least three ways. First, the Agreement and Action Plan represent the first attempt to develop a broad regional marine environmental protection regime in North America . . . . Second, the Agreement is a provincial and state initiative, not a bilateral treaty between two sovereign nations. The Agreement, signed by the governors and premiers of the jurisdictions concerned, is neither a diplomatic instrument, nor a formal document. It is, essentially, a non-binding, multilateral, political agreement and therefore the impetus to cooperate is moral, rather than as a result of any legal obligation or commitment. This is in contrast to most regional marine environmental arrangements . . . which involve countries, such as the 13 Regional Seas Programmes facilitated by the United Nations Environmental Programme (UNEP) and the regional agreements for the Baltic and North-East Atlantic. Third, the Agreement and Action Plan are not limited in coverage to marine waters but adopt an ecosystem approach covering coastal areas and watersheds in the region. The Agreement explicitly provides for consideration of “the shoreline, seabed, waters and associated natural resources of the GoM region, including Georges Bank and the Bay of Fundy.” The GoM regime has persisted for two decades and has grown to address increasingly more issues. It has evolved to respond to a changing biophysical and socio-economic operating environment in a different manner from other regional environmental regimes, and continues to do so with the release of its fourth and latest Action Plan for the period 2007-2012. Against this backdrop, this Article is an assessment of the GoM regime, and further builds on the literature on the subject. This assessment is considered in the context of the GoM’s geography, hydrology, ecosystem, resources, and legal considerations, and the ecosystem challenges faced by the region. The origins and historical evolution of the regime are then set out, followed by a discussion of the main elements of the GoM regime. This assessment is an attempt at explaining the persistence of the GoM regime by offering insights into key factors that have contributed to its endurance, while at the same time raising important questions for future continuity and further growth