neoKREEP: A new lunar component at Apollo 17

The Apollo 11 (Mare Tranquillitatis) and Apollo 17 (Mare Serenitatis) landing sites are important as the only sources of high-Ti basalt visited by the Apollo missions. The lunar high-Ti basalts (greater than 6 percent TiO2) have no volumetrically comparable analogs among terrestrial basalts and require the presence of ilmenite in the source region, probably representing cumulates produced late in the crystallization of the lunar magma ocean. Six principal groups of high-Ti basalts are described, three from each of the two sites

Fabrication of glass fiber-reinforced transparent composites using vacuum assisted resin transfer molding process

The most commonly used transparent material is glass. Traditionally, glass is not desired for applications involving a low weight material while preserving high strength such as aerospace and military applications where armor must also be transparent. Some applications may include aircraft canopies and other vehicle windows. Development of a reliable transparent composite would fill a need for many of these applications where a transparent structure must both be strong and lightweight. A transparent polymer reinforced with a glass fiber fabric is a viable solution. To ensure transparency, both fiber and matrix must match in refractive index. In the present work, transparent composites are manufactured using two vacuum assisted resin transfer molding (VARTM) processes. An E-glass fiber fabric is used as reinforcements and an epoxy-based resin developed at the Missouri University of Science & Technology is used as the matrix. In the VARTM process, the glass fiber preform is placed between two molds for part quality and the mold is sealed with a vacuum bag. Resin is drawn into the mold by a combination of a vacuum and atmospheric pressure to infuse the preform and the part is cured. A second, yet similar VARTM process has been developed to decrease void content and increase transparency of the composite panels through the elimination of air bubbles concentrated at the initial stages of infusion --Abstract, page iii

Melting of cognetic depleted and enriched reservoirs and the production of high Ti Mare basalts

Implicit in current understanding of the location of terrestrial enriched and depleted reservoirs is the notion that they are spatially separated. The depleted reservoir on Earth is situated in the upper mantle, and the complementary enriched reservoir is located in the crust. However, Earth reservoirs are continually being modified by recycling driven by mantle convection. The Moon is demonstrably different from Earth in that its evolution was arrested relatively early - effectively with 1.5 Ga of its formation. It is possible that crystallized trapped liquids (from the late stages of a magma ocean) have been preserved as LILE-enriched portions of the lunar mantle. This would lead to depleted (cumulate) and enriched (magma ocean residual liquid) reservoirs in the lunar upper mantle. There is no evidence for significant recycling from the highland crust back into the mantle. Therefore, reservoirs created at the Moon's inception may have remained intact for over 4.0 Ga. The topics discussed include the following: (1) radiogenic isotopes in high-Ti mare basalts; (2) formation of cogenetic depleted and enriched reservoirs; and (3) melting of the source to achieve high-Ti mare basalts

Constraints on the genesis and evolution of the Moon\u27s magma ocean and derivative cumulate sources as supported by lunar meteorites

It is generally considered that the outer portion of the Moon was molten in its early history. Antarctic lunar meteorites support this supposition, indicating the presence of a global plagioclase-rich crust derived from magma ocean flotation cumulates. Lunar meteorites also contain a significant very low-Ti (VLT) mare basalt component which was likely generated by the melting of a cumulate mantle formed in an early moon-wide magma ocean. Early in the evolution of the mantle, when the lunar magma ocean (LMO) still was largely liquid, it is likely that vigorous convection was an important factor in crystallization. Such convection would allow crystals to remain suspended and in equilibrium with the LMO liquid for relatively long periods of time. This extended period of equilibrium crystallization would then have been followed by fractional crystallization once plagioclase became a liquidus phase and began to float to form the lunar highlands crust. The residual liquid after 80-90 percent crystallization was very evolved (in fact KREEPy) and, even in small proportions (1-5%), would have a noticeable effect on the trace-element chemistry of melts generated from these cumulates. This trapped residual liquid would elevate total REE abundances in the cumulate pile, while synchronously deepening the already negative Eu anomaly. The LMO liquid calculated after extensive crystallization (>99.5% crystallized) has a composition which is similar to that recorded in quartz monzodiorites. This evolved liquid could be represented by the sparse KREEP component found in lunar meteorites. The mare basalt component found in such meteorites as EET87521 can be generated by fractional crystallization of a more primitive magma similar in composition to Apollo VLT picritic glass beads. This picritic magma can be produced by melting of a cumulate source in the lunar upper mantle

Depletion of atmospheric nitrate and chloride as a consequence of the Toba Volcanic Eruption

Continuous measurements of SO42− and electrical conductivity (ECM) along the GISP2 ice core record the Toba mega‐eruption at a depth 2590.95 to 2091.25 m (71,000±5000 years ago). Major chemical species were analyzed at a resolution of 1 cm per sample for this section. An ∼6‐year long period with extremely high volcanic SO42− coincident with a 94% depletion of nitrate and 63% depletion of chloride is observed at the depth of the Toba horizon. Such a reduction of chloride in a volcanic layer preserved in an ice core has not been observed in any previous studies. The nearly complete depletion of nitrate (to 5 ppb) encountered at the Toba level is the lowest value in the entire ∼250,000 years of the GISP2 ice core record. We propose possible mechanisms to explain the depletion of nitrate and chloride resulting from this mega‐eruption

The Jet-Driven Outflow In The Radio Galaxy SDSS J1517+3353: Implications For Double-Peaked Narrow-Line Active Galactic Nucleus

We report on the study of an intriguing active galaxy that was selected as a potential multiple supermassive black hole merger in the early-type host SDSS J151709.20+335324.7 (z = 0.135) from a complete search for double-peaked [O III] lines from the SDSS spectroscopic quasi-stellar object (QSO) database. Ground-based SDSS imaging reveals two blue structures on either side of the photometric center of the host galaxy, separated from each other by about 5.7 kpc. From a combination of SDSS fiber and Keck/HIRES long-slit spectroscopy, it is demonstrated that, in addition to these two features, a third distinct structure surrounds the nucleus of the host galaxy. All three structures exhibit highly ionized line emission with line ratios characteristic of Seyfert II active galactic nuclei. The analysis of spatially resolved emission-line profiles from the HIRES spectrum reveal three distinct kinematic subcomponents, one at rest and the other two moving at -350 km s(-1) and 500 km s(-1) with respect to the systemic velocity of the host galaxy. A comparison of imaging and spectral data confirm a strong association between the kinematic components and the spatial knots, which implies a highly disturbed and complex active region in this object. A comparative analysis of the broadband positions, colors, kinematics, and spectral properties of the knots in this system lead to two plausible explanations: (1) a multiple active galactic nucleus (AGN) produced due to a massive dry merger, or (2) a very powerful radio jet-driven outflow. Subsequent VLA radio imaging reveals a clear jet aligned with the emission-line gas, confirming the latter explanation. We use the broadband radio measurements to examine the impact of the jet on the interstellar medium of the host galaxy, and find that the energy in the radio lobes can heat a significant fraction of the gas to the virial temperature. Finally, we discuss tests that may help future surveys distinguish between jet-driven kinematics and true black-hole binaries. J1517+3353 is a remarkable laboratory for AGN feedback and warrants deeper follow-up study. In the Appendix, we present high-resolution radio imaging of a second AGN with double-peaked [O III] lines, SDSS J112939.78+605742.6, which shows a sub-arcsecond radio jet. If the double-peaked nature of the narrow lines in radio-loud AGNs are generally due to radio jet interactions, we suggest that extended radio structure should be expected in most of such systems.NSF AST-0507483, AST-0808133University of Texas at AustinAlfred P. Sloan FoundationParticipating InstitutionsNational Aeronautics and Space AdministrationU.S. Department of EnergyJapanese MonbukagakushoMax Planck SocietyAstronom

Geochemical and isotopic evidence bearing on the origin of large, igneous-textured inclusions in ordinary chondrites

Geochemical and isotopic data for large, igneous-textured inclusions in ordinary chondrites suggest that the inclusions formed by the melting of diverse precursors, and that various inclusions had different origins. Some inclusions were metasomatized (chemically altered) and metamorphosed, and many appear to have degassed argon in late shock events. The inclusions can be subdivided into two chemical groups, Na-rich (Na/Al>0.35 at.) and Na-poor (≤0.35), which may have originated in different ways. The major-and trace-element abundances of Na-rich inclusions are best explained by these inclusions having formed by the shock-melting of ordinary chondrites, often accompanied by loss of FeNi-metal and sulfide and by preferential melting and accumulation of an albitic feldspar component. In contrast, there is no evidence that shock-melting was involved in the formation of Na-poor inclusions, which have compositions that were largely controlled by vapor-fractionation processes. It is suggested that the precursors to Na-poor inclusions consisted of mixtures of vapor-fractionated materials in a system of condensed phases that chemically resembled CI-chondrites, except for being depleted in volatile-lithophile elements and in metal and sulfide. Sodium-poor inclusions can be subdivided into two types, Trend A and Trend B, which differ in their trace-element characteristics, in the nature of their compositional variations, and in their inferred precursors. Trend A Na-poor inclusions are enriched in refractory elements, and could have formed by the melting of mixtures containing a chondritic (CI-like) component and a refractory (Al-rich, CAI-like) component. Trend B Na-poor inclusions are enriched in elements of intermediate volatility (Si) and appear to have formed from precursors that lost both a refractory (Mg-rich, olivine-rich) and a volatile component. The precursors to these inclusions could have been produced by the removal of an olivine-rich condensate during fractional condensation, or by the condensation of Si-rich gases during fractional vaporization

Potential atmospheric impact of the Toba Mega‐Eruption ∼71,000 years ago

An ∼6‐year long period of volcanic sulfate recorded in the GISP2 ice core about 71,100 ± 5000 years ago may provide detailed information on the atmospheric and climatic impact of the Toba mega‐eruption. Deposition of these aerosols occur at the beginning of an ∼1000‐year long stadial event, but not immediately before the longer glacial period beginning ∼67,500 years ago. Total stratospheric loading estimates over this ∼6‐year period range from 2200 to 4400 Mt of H2SO4 aerosols. The range in values is given to compensate for uncertainties in aerosol transport. Magnitude and longevity of the atmospheric loading may have led directly to enhanced cooling during the initial two centuries of this ∼1000‐year cooling event

Author Correction: A cell-free platform for the prenylation of natural products and application to cannabinoid production.

In the original version of this Article, the genotype of the M30 mutant presented in Fig. 3b was given incorrectly as Y288V/A232S, and the M31 mutant was given incorrectly as M1/A232S. The correct genotype of the M30 mutant is Y288A/A232S and for M31 it is Y288V/A232S. In addition, to keep consistency in genotype formatting, the genotype of the M27 mutant should be Y288V/G286S. The errors have been corrected in both the PDF and HTML versions of the Article

Agribusiness Capstone Courses Design: Objectives and Strategies

This paper discusses the benefits of using strategic management principles as the cornerstone for building the agribusiness capstone experience. The necessity for agribusiness firms to create and implement strategies that build a sustainable competitive advantage in turn necessitates the development of strategic management skills in the leaders/managers of the future. As such, the objectives of a capstone course lean heavily toward the integrative development of strategic decision-making competence. This has a number of implications for the capstone professor in terms of course content, pedagogies, and subsequent measurement of student performance.Agribusiness, Teaching/Communication/Extension/Profession,