Luminous efficiency of an artificial meteor at 11.9 kilometers per second

Trailblazer II reentry vehicle artificial meteoroid experiment consisting of reentering 2.2-gram stainless steel pellet into eart

Historical background and design evolution of the transonic aircraft technology supercritical wing

Two dimensional wind tunnel test results obtained for supercritical airfoils indicated that substantial improvements in aircraft performance at high subsonic speeds could be achieved by shaping the airfoil to improve the supercritical flow above the upper surface. Significant increases in the drag divergence Mach number, the maximum lift coefficient for buffer onset, and the Mach number for buffet onset at a given lift coefficient were demonstrated for the supercritical airfoil, as compared with a NACA 6 series airfoil of comparable thickness. These trends were corroborated by results from three dimensional wind tunnel and flight tests. Because these indicated extensions of the buffet boundaries could provide significant improvements in the maneuverability of a fighter airplane, an exploratory wind tunnel investigation was initiated which demonstrated that significant aerodynamic improvements could be achieved from the direct substitution of a supercritical airfoil on a variable wing sweep multimission airplane model

Evaluating the Current Weed Community in Wild Blueberry Fields and IPM Strategies for Spreading Dogbane (Apocynum androsaemifolium)

Lowbush blueberry (Vaccinium angustifolium) is Maine’s third largest crop (USDA 2020 a). From 2017 – 2019 the three seasons yield average was 27,200 tons were harvested from 19,500 acres for a value of $22,468,000 (USDA 2020 c). Lowbush blueberries are managed on a two-year cycle. Every other year, lowbush blueberry fields are pruned to the ground either through the use of a tractor mounted flail mower or a prescribed burn (Yarborough 2009). Pruning is a necessary part of managing lowbush blueberries as the second-year growth produces the highest yield but steadily declines in subsequent years (Drummond et al. 2008; DeGomez 1988). This practice is not detrimental to the lowbush blueberry as approximately 70% of the plant grows underground (Drummond et al. 2008). After a prune, lowbush blueberries regrow for the following year in what is referred to as the “prune” year. Floral buds develop over the prune year and overwinter into the next year, referred to as the “crop” year (Yarborough 2009). In May of the crop year, the floral buds open into small-bell shaped flowers and remain open for three to four weeks. Lowbush blueberry flowers are typically not self-fertile and require the use of pollinators. Most farmers will supplement their pollination by renting commercial beehives, increasing the yield (Yarborough 2019). Berries form from the pollinated flowers by the end of July to August (Yarborough 2009). Harvests involve the use of either large mechanical harvesters or teams using hand rakes. Mechanical harvesters are the more common tool for harvesting, as they are used in 80% of the fields in Maine (Yarborough 2009). Farm crews remove debris from what was harvested, and berries are either sold fresh or delivered to one of many commercial freezers. Frozen berries are then packaged for the retail market or processed further into a range of value-added products (Calderwood and Tooley 2020). A common challenge for farmers is the presence of weeds within their fields. Weeds take up valuable shade, nutrients and space that would otherwise be utilized by the lowbush blueberry. Weeds can reduce yield, increase disease incidence and interfere with harvest operations. Up to 84% of yield can be lost because of weed cover (Yarborough 2009; Yarborough and Mara 1997). The moisture created by the additional canopy of weeds can increase the incidence of harmful diseases such as mummy berry (Monilinia vaccinii-corymbosi) (Drummond et al. 2012). Weeds can interfere with the efficiency of mechanical harvesters as they get caught within the harvested berries (Yarborough 2009). Despite these negative effects, there has not been a weed survey of lowbush blueberry fields in the state of Maine since 1980 (Yarborough and Marra 1997). Weed surveys are important for farmers to evaluate their current weed management strategies and to discover possible trends in the weed community. One of the most difficult weeds to manage within wild blueberry fields is spreading dogbane (Apocynum androsaemifolium). It resists at least six common herbicides (NBDAAF 2017) and can form dense patches through its rhizomes (Niering et al. 2001)

Effects of Neighboring Nectar-Producing Plants on Populations of Pest Lepidoptera and Their Parasitoids in Broccoli Plantings

Eggs and larvae of the imported cabbageworm, Pieris rapae, were much more abundant in broccoli interplanted with nectar-producing plants than in broccoli monoculture. More diamondback moth larvae, Plutella xylostella, occurred in broccoli interplanted with or adjacent to nectar-producing plants than in broccoli monoculture. Density of cabbage looper larvae, Trichoplusia ni, was similar among the three types of broccoli plantings. For Cotesia rubecula, established in Michigan after introduction from Yugoslavia, pupae were more numerous in broccoli interplanted with nectar-producing plants than in other plots. High parasitism rates of diamondback moth, mainly by Diadegma insulare, were observed in every plot, but there were no differences in parasitism of diamondback moth between the treatments. Results indicate that the interactions between pests, parasitoids and nectar-producing plants are complex and may be different for each species

Photographic observations of 10 artificial meteors

Photographic observation of artificial meteo

A Wind-Tunnel Investigation of the Application of the NASA Supercritical Airfoil to a Variable-Wing-Sweep Fighter Airplane

An investigation was conducted in the Langley 8 foot transonic pressure tunnel and the Langley Unitary Plan wind tunnel to evaluate the effectiveness of three variations of the NASA supercritical airfoil as applied to a model of a variable wing sweep fighter airplane. Wing panels incorporating conventional NACA 64A series airfoil with 0.20 and 0.40 camber were used as bases of reference for this evaluation. Static force and moment measurements were obtained for wing leading edge sweep angles of 26, 33, 39, and 72.5 degrees. Fluctuating wing root bending moment data were obtained at subsonic speeds to determine buffet characteristics. Subsonic data were also obtained for determining the effects of wing transition location and spoiler deflection. Limited lateral directional data are included for the conventional 0.20 cambered wing and the supercritical wing

Effect of wing-transition location and slotted and unslotted flaps on aerodynamic characteristics of a fighter model at high subsonic speeds

An investigation was conducted in the Langley 8 foot transonic pressure tunnel to determine the effects of wing transition location and of slotted and unslotted full span flaps on the longitudinal aerodynamic characteristics of a 1/15 scale model of a variable wing sweep tactical fighter model. Tests were at Mach numbers from 0.70 to 0.85 for a wing leading edge sweep of 26 deg

Haze in the Klang Valley of Malaysia

Continuous measurements of dry aerosol light scattering (Bsp) were made at two sites in the Klang Valley of Malaysia between December 1998 and December 2000. In addition 24-h PM2.5 samples were collected on a one-day-in-six cycle and the chemical composition of the aerosol was determined. Periods of excessive haze were defined as 24-h average Bsp values greater than 150 Mm-1 and these occurred on a number of occasions, between May and September 1999, during May 2000, and between July and September 2000. The evidence for smoke being a significant contributor to aerosol during periods of excessive haze is discussed and includes features of the aerosol chemistry, the diurnal cycle of Bsp, and the coincidence of forest fires on Sumatra during the southwest (SW) monsoon period, as well as transport modelling for one week of the southwest Monsoon of 2000. The study highlights that whilst transboundary smoke is a major contributor to poor visibility in the Klang Valley, smoke from fires on Peninsular Malaysia is also a contributor, and at all times, the domestic source of secondary particle production is present

Passivity, being-with and being-there: care during birth

This paper examines how to best be with women during birth, based on a phenomenological description of the birth experience. The first part of the paper establishes birth as an uncanny experience, that is, an experience that is not only entirely unfamiliar, but even unimaginable. The way in which birth happens under unknowable circumstances (in terms of when, how, with whom…) creates a set of anxieties on top of the fundamental anxiety that emerges from the existential paradox by which it does not seem possible for a body to give birth to another body. Would homebirth provide a remedy to the uncanniness? The result yielded by medical studies is confirmed by the phenomenological perspective taken here: homebirth might be reassuring for some, but not for everybody; choice of birth place is important. Once the birth process starts happening, another layer of strangeness is added: it turns out to be an experience of radical passivity and waiting, normally. The question thus becomes how to best care for somebody who is exposed to uncanniness, passivity, and waiting. Martin Heidegger’s concepts of care and discourse prove useful in examining how to facilitate rather than interrupt this process. It becomes necessary to think beyond verbal communication towards a wider concept of communication that involves silence and intercorporeality. Birth requires a special kind of being-with as being-there

Electrophoresis Staining: a New Method of Whole Mount Staining

Advances in tissue clearing techniques have allowed almost a ten-fold increase in the viewing depth of confocal microscopy. This allows for intact cellular structures to be rendered in 3D. However, viewing tissues to this depth is often limited to endogenous fluorescence as passive diffusion of antibodies via whole mount staining can take weeks. Our lab is developing a new method involving electrophoresis as a driving force that will promote active antibody binding deep into tissue, reducing the amount of time needed to stain for cellular structures. Due to the inherent charge within antibodies, they are able to be directionally forced through a mouse embryo which has been embedded in agarose. As the antibodies progress through the mouse embryo, they are able to bind to their epitope. Through this method, effective antibody staining of blood vessels was accomplished in a mouse embryo in a reduced amount of time in contrast to traditional staining methods, such as whole mount staining. With this new staining technique, combined with tissue clearing, complex cellular structures can be observed in intact tissues with the use of confocal microscopy