Computer program provides improved longitudinal response analysis for axisymmetric launch vehicles

Computer program calculates axisymmetric launch vehicle steady-state response to axisymmetric sinusoidal loads. A finite element technique is utilized to construct the total launch vehicle stiffness matrix and mass matrix by subdividing the prototype structure into a set of axisymmetric shell components, fluid components, and spring-mass components

Dispersants and Seafood Safety Assessment of the potential impact of Corexit® oil dispersants on seafood safety

The April 20, 2010 explosion and subsequent sinking of the Deepwater Horizon oil production platform (DWH) resulted in the largest oil spill in U.S. history. On April 29th, a Spill of National Significance was declared as roughly 53 thousand barrels of oil per day flowed into the Gulf of Mexico (GOM). The U.S. Coast Guard estimated 4.9 million barrels of crude oil escaped before the damaged DWH wellhead was sealed on July 15, 2010 (National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling 2010). Oil spill clean-up methods included skimming operations, burning of surface oil, siphoning oil into tankers directly from the wellhead, and the application of chemical dispersants. The first 3 methods mentioned above physically removed spilled oil from GOM waters. The last method, chemical dispersion, distributed insoluble fractions of the oil into the water-column. This was done for 3 reasons: 1) to reduce the exposure of response personnel at-sea to volatile organic compounds emanating from the surface slick; 2) to prevent concentrated surface oil from reaching, and damaging, fragile coastal wetlands, beaches and shoreline communities; and 3) to accelerate the break-down of spilled oil by natural microorganisms in the environment. The oil spill response contingency plan (RCP) applicable to the GOM (EPA Regions 4 and 6 within the National Response Plan framework) pre-authorized the use of Nalco Co. (Naperville, IL) oil dispersants Corexit® 9527 and Corexit® 9500 among other pre-approved product formulations. From April 22 to July 19, 2010 an estimated 1.1 million gallons of Corexit® dispersant were applied over approximately 300 square miles of oiled surface waters in the GOM and 771,000 gallons were injected directly into the oil free-flowing from the wellhead 5,100 feet beneath the surface (National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling 2010). Corexit® 9527 comprised approximately 215,000 gallons (~11%) of the total dispersant volume applied to the surface oil slick and was discontinued on May 22. The unprecedented volume of chemical dispersants used to combat the DWH oil spill elicited public concerns for the health of responders, coastal communities, marine life, and the safety of seafood from impacted areas of the GOM. This document will address the latter of these concerns

An Intrinsic Approach to Forces in Magnetoelectric Media

This paper offers a conceptually straightforward method for the calculation of stresses in polarisable media based on the notion of a drive form and its property of being closed in spacetimes with symmetry. After an outline of the notation required to exploit the powerful exterior calculus of differential forms, a discussion of the relation between Killing isometries and conservation laws for smooth and distributional drive forms is given. Instantaneous forces on isolated spacetime domains and regions with interfaces are defined, based on manifestly covariant equations of motion. The remaining sections apply these notions to media that sustain electromagnetic stresses, with emphasis on homogeneous magnetoelectric material. An explicit calculation of the average pressure exerted by a monochromatic wave normally incident on a homogeneous, magnetoelectric slab in vacuo is presented and the concluding section summarizes how this pressure depends on the parameters in the magnetoelectric tensors for the medium.Comment: 25 pages, 3 figures, to appear in Il Nuovo Cimento B, proceedings of GCM8, Catania (Oct 2008) - References added, minor corrections mad

The foaming of lavas

Foaming is of great practical and theoretical significance for volcanic processes on the earth, the moon, and perhaps the meteorite parent bodies. The theory of foams agrees with steelmaking experience to indicate that their presence depends on the existence of solutes in the lavas which reduce the surface tension, and are not saturated. These solutes concentrate at the surface, and are called surfactants. The surfactant responsible for the formation of volcanic ash was not identified; it appears to be related to the oxygen partial pressure above the lava. This fact may explain why lunar and meteoritic melts are not observed to foam. Experimental studies are needed to clarify the process

Diurnal Retreats of Bats

The forelimbs of bats are so highly modified for flight that they are of little value for terrestrial locomotion. Deprived of all but limited use of the front feet in terrestrial activity, roosts or resting sites are also limited. All bats are primarily nocturnal and most of them spend the day in elevated, secluded retreats. Elevation is critical, for some bats show limited ability to take flight from flat, horizontal surfaces. Many bats, however, do show marked agility on the ground, and are quite capable of gaining flight from flat, horizontal surfaces. There is little correlation between taxonomy and roosting habits, although utilization of vegetation as roosts appears to be the general rule in the Megachiroptera and rather uncommon in the Microchiroptera

Post-Cranial Osteology of Bats

Fossil bats give few clues to the early evolution of the Chiroptera. Adaptations for flight were well established by early Eocene, and osteological characters of Recent Chiroptera show only minor changes since the Eocene. Examination of the post-cranial skeleton reveals these important general features: (1) arch, anteroposterior compression and partial fusion of the vertebral column; (2) well developed pectoral girdle with large clavicles and a small keel present on the sternum; (3) secondary humeroscapular association; (4) modification of the forearm for flight with the ulna rudimentary and the metacarpals and phalanges elongated to spread the flight membranes; (5) weak hind limbs, incomplete fibula; and (6) well developed hind feet

Comparative Osteology of the Pelvic Girdles of the Phyllostomatidae (Chiroptera; Mammalia)

The Chilonycterinae are the most primitive of the subfamilies of the Phyllostomatidae. Two basic groups comprise this subfamily: the first includes the genera Pteronotus and Chilonycteris; the second, the genus Mormoops. This grouping is based principally upon the characteristics of the humerus and the innominate. Within the subfamily Phyllostomatinae two types are recognized. The Macrotus-type is considered the more primitive, because of its resemblance to the chilonycterines, and the Phyllustomus-type the more advanced. From these two phyllostomatine groups are derived the more advanced lines of the Phyllostomatidae. The phyllonycterine line appears to be derived from the Macrotus-type. The sturnirine-glossophagine line and the stenodcrmine line are derived from the Phyllostomus-type. The Vam pyrops-type of stenodermine shows affinities with the glossophagines and is considered the more primitive stenodermine. The Artibrns-type stenodermine is considered the more advanced. The carolline group shows relationships to the Macrotus-type of phyllostomatine and also shows affinities with the sturnirines. A more thorough study of the genera involved is needed to determine this relationship. The family Phyllostomatidae has its closest affinities with the Desmodontidae, and post-cranial evidence offers little reason to consider these as separate families. Other close relationships of the Phyllostomatidae appear to exist with the Noctilionidae and possibly with the Emballonuridae