Advantages of Oxide Films as Bases for Aluminum Pigmented Surface Coatings for Aluminum Alloys

Both laboratory and weather-exposure corrosion tests showed conclusively that the protection afforded by aluminum pigmented spar varnish coatings applied to previously anodized aluminum surfaces was greatly superior to that afforded by the same coatings applied to surfaces which had simply been cleaned free from grease and not anodized

Methods for the Identification of Aircraft Tubing of Plain Carbon Steel and Chromium-Molybdenum Steel

The survey of the possibilities for distinguishing between plain carbon and chromium-molybdenum steel tubing included the Herbert pendulum hardness, magnetic, sparks, and chemical tests. The Herbert pendulum test has the disadvantages of all hardness tests in being limited to factory use and being applicable only to scale-free, normalized material. The small difference in the range of hardness values between plain carbon and chromium-molybdenum steels is likewise a disadvantage. The Rockwell hardness test, at present used in the industry for this purpose, is much more reliable. It may be concluded on the basis of the experiments performed that of all methods surveyed, spark testing appears to be, at present, the most suitable for factory use from the standpoint of speed, accuracy, nondestructiveness and reliability. It is also applicable for field use

Hubble Space Telescope Observations of 3200 Phaethon At Closest Approach

We present Hubble Space Telescope observations of the active asteroid (and Geminid stream parent) 3200 Phaethon when at its closest approach to Earth (separation 0.07 AU) in 2017 December. Images were recorded within $\sim$1\degr~of the orbital plane, providing extra sensitivity to low surface brightness caused by scattering from a large-particle trail. We placed an upper limit to the apparent surface brightness of such a trail at 27.2 magnitudes arcsecond$^{-2}$, corresponding to an in-plane optical depth $\le 3\times10^{-9}$. No co-moving sources brighter than absolute magnitude 26.3, corresponding to circular equivalent radius $\sim$12 m (albedo 0.12 assumed), were detected. Phaethon is too hot for near-surface ice to survive. We briefly consider the thermodynamic stability of deeply-buried ice, finding that its survival would require either a very small (regolith-like) thermal diffusivity ($< 10^{-8}$ m$^2$ s$^{-1}$), or the unexpectedly recent injection of Phaethon (timescale $\lesssim$ 10$^6$ yr) into its present orbit, or both.Comment: Improved the discussion of optical depth calculation and corrected an error in the previous version. 28 pages, 5 figures, Astronomical Journal, in pres

The Algae of a Transient Lake in Kentucky

The present taxonomical study was undertaken with the view of obtaining additional information on the occurrence and distribution of algae in Kentucky. The investigation was begun in February 1934 under the direction of Dr. H.L. Stephens of the Western Kentucky State Teachers College. During the next three months 110 collections of algae were made and analyzed

Planning for an Age-Friendly Belmont

Belmont is a primarily residential community of around 25,000 residents with a small commercial district. Public transit access to downtown Boston and neighboring Cambridge offers Belmont residents access to services, employment, and recreational activities outside of the town’s boundaries. With 22% of its population age 60 and older, Belmont is expecting to see an increase in the number of older residents in the coming years. Commissioned by the Belmont Council on Aging (COA), this report will serve to help the COA and Town to better understand Belmont’s current assets, potentials, and challenges and to plan for changing community needs

Marshfield Council on Aging Planning Study

This report describes collaborative efforts undertaken by the Town of Marshfield Council on Aging (COA) and the Center for Social and Demographic Research on Aging (CSDRA), within the Gerontology Institute at the McCormack Graduate School, University of Massachusetts Boston. Beginning in Fall 2017, these organizations partnered to conduct a study to investigate the needs, interests, preferences, and opinions of the Town’s residents age 50+, and also of participants at the Marshfield COA/Senior Center. During this assessment, several approaches were utilized to compile information that could be used to plan and implement current and future services. We examined data from the U.S. Census Bureau and from projections generated by the Donahue Institute at the University of Massachusetts, and by the Metropolitan Area Planning Council (MAPC) to describe growth of the population in the past and changes that can be expected in the future. We developed and administered an online survey for Marshfield residents age 50 and older (referred to here as the online community survey), and developed another survey for Marshfield COA/Senior Center participants (the walk-in participant survey). In addition, we collected insights from Marshfield leadership, COA Board members, staff and volunteers

The Extraordinary Multi-Tailed Main-Belt Comet P/2013 P5

Hubble Space Telescope observations of main-belt comet P/2013 P5 reveal an extraordinary system of six dust tails that distinguish this object from any other. Observations two weeks apart show dramatic morphological change in the tails while providing no evidence for secular fading of the object as a whole. Each tail is associated with a unique ejection date, revealing continued, episodic mass loss from the 0.24+/-0.04 km radius nucleus over the last five months. As an inner-belt asteroid and probable Flora family member, the object is likely to be highly metamorphosed and unlikely to contain ice. The protracted period of dust release appears inconsistent with an impact origin, but may be compatible with a body that is losing mass through a rotational instability. We suggest that P/2013 P5 has been accelerated to breakup speed by radiation torques.Comment: 13 pages, two figures, three tables, Accepted to ApJ

A binary main belt comet

The asteroids are primitive solar system bodies which evolve both collisionally and through disruptions due to rapid rotation [1]. These processes can lead to the formation of binary asteroids [2-4] and to the release of dust [5], both directly and, in some cases, through uncovering frozen volatiles. In a sub-set of the asteroids called main-belt comets (MBCs), the sublimation of excavated volatiles causes transient comet-like activity [6-8]. Torques exerted by sublimation measurably influence the spin rates of active comets [9] and might lead to the splitting of bilobate comet nuclei [10]. The kilometer-sized main-belt asteroid 288P (300163) showed activity for several months around its perihelion 2011 [11], suspected to be sustained by the sublimation of water ice [12] and supported by rapid rotation [13], while at least one component rotates slowly with a period of 16 hours [14]. 288P is part of a young family of at least 11 asteroids that formed from a ~10km diameter precursor during a shattering collision 7.5 million years ago [15]. Here we report that 288P is a binary main-belt comet. It is different from the known asteroid binaries for its combination of wide separation, near-equal component size, high eccentricity, and comet-like activity. The observations also provide strong support for sublimation as the driver of activity in 288P and show that sublimation torques may play a significant role in binary orbit evolution.Comment: 18 pages, 8 figures, 2 table

Episodic Ejection from Active Asteroid 311P/PANSTARRS

We examine the development of the active asteroid 311P/PANSTARRS (formerly, 2013 P5) in the period from 2013 September to 2014 February using high resolution images from the Hubble Space Telescope. This multi-tailed object is characterized by a single, reddish nucleus of absolute magnitude $H \ge$ 18.98$\pm$0.10, corresponding to an equal-area sphere of radius $\le$200$\pm$20 m (for assumed geometric albedo 0.29$\pm$0.09). We set an upper limit to the radii of possible companion nuclei at $\sim$10 m. The nucleus ejected debris in nine discrete episodes, spread irregularly over a nine month interval, each time forming a distinct tail. Particles in the tails range from about 10 $\mu$m to at least 80 mm in radius, and were ejected at speeds $<$1 m s$^{-1}$. The ratio of the total ejected dust mass to the nucleus mass is $\sim$3$\times$10$^{-5}$, corresponding to a global surface layer $\sim$2 mm thick, or to a deeper layer covering a smaller fraction of the surface. The observations are incompatible with an origin of the activity by impact or by the sublimation of entrapped ice. This object appears to be shedding its regolith by rotational (presumably YORP-driven) instability. Long-term fading of the photometry (months) is attributed to gradual dissipation of near-nucleus dust. Photometric variations on short timescales ($<$0.7 hr) are probably caused by fast rotation of the nucleus. However, because of limited time coverage and dilution of the nucleus signal by near-nucleus dust, we have not been able to determine the rotation period.Comment: 37 pages, 12 figure