High level sill and dyke intrusions initiated from rapidly buried mafic lava flows in scoria cones of Tongoa, Vanuatu (New Hebrides), South Pacific

Scoria cones are generally considered to grow rapidly in days to weeks or months. During their growth lava flows may be fed onto the cone surface from lava-lake breaches, or form by coalescence of spatter; such flows are preserved interbedded with scoria lapilli and ash beds. On Tongoa, an island of the Vanuatu volcanic arc in the South Pacific, a series of scoria cones developed during the Holocene, forming a widespread monogenetic volcanic field. Half sections of scoria cones along the coast expose complex interior architecture cone architectures. On the western side of Tongoa Island a scoria cone remnant with steeply crater-ward dipping beds of scoria ash and lapilli contains various dm-to-m thick lava flows, which are connected by irregular dikes cutting obliquely across the beds of the cone. The lava flows are coherent igneous bodies with well-developed flow top and basal breccias. The lavas interbedded with the cone-forming layers are part of a larger (up to 7 m thick) body that is connected to dykes and sills of irregular geometries that intrude the cone's pyroclastic layers. This 3D relationship suggests that the lava flows were buried quickly under the accumulating scoriaceous deposits. This allowed subsequent escape of magma from the fluid interiors of flows, with the magma then squeezed upward or laterally into the accumulating pyroclastic pile. Movement of the pile above the partly mobile lava, and potential destabilisation during intrusion into the pile of lava squeezed from the flows, may signal the onset of localised cone failures, and could be implicated in development of major cone breaches (e.g. Paricutin)

History of the Confederate General Hospital Located at Farmville Va. 1862-65

The History of the Confederate General Hospital Located at Farmville, VA 1862-65 was published by the Farmville Chapter of the United Daughters of the Confederacy (UDC) on April 7, 1916 by the Martin Printing Company in Farmville. The information found within the fifteen-page book was provided from an 1897 letter addressed to the UDC from James L. White, M. D., who was a surgeon stationed at the hospital during the American Civil War and a citizen of Farmville until his death in 1909. White gives an overview regarding his personal history during the war, others involved with the hospital and its structure, the days leading up to the surrender at Appomattox, Union occupation, the Confederate Cemetery, and the intentions by the UDC to commemorate Confederate soldiers

Compositional variation during monogenetic volcano growth and its implications for magma supply to continental volcanic fields

Individual volcanoes of continental monogenetic volcanic fields are generally presumed to erupt single magma batches during brief eruptions. Nevertheless, in two unrelated volcanic fields (the Waipiata volcanic field, New Zealand, and the Miocene-Pliocene volcanic field in western Hungary), we have identified pronounced and systematic compositional differences among products of individual volcanoes. We infer that this indicates a two-stage process of magma supply for these volcanoes. Each volcano records: (1) intrusion of a basanitic parent magma to lower- to mid-crustal levels and its subsequent fractionation to form a tephritic residual melt;, (2) subsequent transection of this reservoir by a second batch of basanitic melt, with tephrite rising to the surface at the head of the propagating basanite dyke. Eruption at the surface then yields initial tephrite, typically erupted as pyroclasts, followed by eruption and shallow intrusion of basanite from deeper in the dyke. By analogy with similar tephrite-basanite eruptions along rift zones of intraplate ocean-island volcanoes, we infer that fractionation to tephrite would have required decades to centuries. We conclude that the two studied continental monogenetic volcanic fields demonstrate a consistent history of early magmatic injections that fail to reach the surface, followed by capture and partial eruption of their evolved residues in the course of separate and significantly later injections of basanite that extend to the surface and erupt. This systematic behaviour probably reflects the difficulty of bringing small volumes of dense, primitive magma to the surface from mantle source regions. Ascent through continental crust is aided by the presence in the dyke head of buoyant tephrite captured during transection of the earlier-emplaced melt bodies

Increasing Spectrum for Broadband: What Are The Options?

The growth of wireless broadband is a bright spot in the U.S. economy, but a shortage of flexibly licensed spectrum rights could put a crimp on this expansion. Freeing up spectrum from other uses would allow greater expansion of wireless broadband and would bring substantial gains—likely in the hundreds of billions of dollars—for U.S. consumers, businesses, and the federal treasury. ... U.S. experience suggests that it takes at least six years, and possibly over a decade, to complete any large-scale reallocation of spectrum. Thus, for policymakers, the ?projected? need is actually here today. This paper makes three proposals to increase spectrum available for wireless broadband under a flexibly licensed, market-based regime.

The Formation of Brown Dwarfs: Observations

We review the current state of observational work on the formation of brown dwarfs, focusing on their initial mass function, velocity and spatial distributions at birth, multiplicity, accretion, and circumstellar disks. The available measurements of these various properties are consistent with a common formation mechanism for brown dwarfs and stars. In particular, the existence of widely separated binary brown dwarfs and a probable isolated proto-brown dwarf indicate that some substellar objects are able to form in the same manner as stars through unperturbed cloud fragmentation. Additional mechanisms such as ejection and photoevaporation may play a role in the birth of some brown dwarfs, but there is no observational evidence to date to suggest that they are the key elements that make it possible for substellar bodies to form.Comment: Protostars and Planets V, in pres

Interface Slippage Study Between Polyamide 12 and Ethylene Butene Copolymer Melt In Capillary Extrusion

Extrusion of a polyamide 12 (PA12) material through a capillary die coated with an ethylene butene copolymer (EBM) was studied. The EBM coated die significantly increased the flow rates of the PA12 melt compared to a clean die at the same extrusion pressure. Introducing a maleic anhydride grafted ethylene-octene copolymer (EOM-g-MAH) into the EBM suppressed the effect. This behavior seems only explained by significant interface slippage between PA12 and EBM melts, which could be eliminated by introducing covalent chemical bonds across the interface. A mathematical analysis was carried out to calculate the interface slippage. The shear stress where slippage began to occur was around 0.045 MPa and the slippage velocity was around 15 mm/s at 0.1 MPa. Adding EOM-g-MAH could largely decrease the interfacial tension between EBM and PA12, thus largely decrease the interface slippage. (C) 2009 The Society of Rheology [DOI: 10.1122/1.3198245

Vendor and Professional Certification Where is it Headed?

Trade journals and magazines define three categories of computer certification: professional, industry, and vendor. The purpose of this study was to compare Information Systems IS) professionals\u27 value of professional and vendor certification types in relation to technical and management positions in IS. It appears that IS professionals value both certification types equally when not considering job position. Findings suggest technical and managerial IS professionals value the two types of certifications differently when job position is considered. Future research is warranted to determine why the respondents considered these two certifications differently for both technical (programmers and analysts) and managerial positions

Experimental And Theoretical Study Of The Sign Preference In The Nucleation Of Water Vapor

The nucleation of water vapor on ions in atmospheres of helium and argon was studied using an expansion type cloud chamber. Separation of the positive and negative ions was achieved so that the nucleation could be studied as a function of both the sign of the ionic charge and the supersaturation. A semiphenominological theory was developed as an extension of the classical liquid drop theory to include the effects of the ionic charge on the nucleation process. The theoretical model of the prenucleation embryo was assumed to possess an oriented dipole surface layer with the direction of orientation dependent on the sign of the ionic charge. The theory predicts not only the increase in the nucleation rate compared to that for homogeneous nucleation and a difference in rate between positive and negative ions, the negative ions having the higher nucleation rate, but also predicts a correction term to the classical theory of homogeneous nucleation for polar molecules which exhibit an electrical double layer at the liquid surface. Comparison of the theoretical and experimental results for nucleation on both positive and negative ions yields good agreement and indicates the prenucleation embryo is probably a tightly bonded highly structured cluster possessing an oriented dipole surface layer. © 1971