Lunar surface dynamics: Some general conclusions and new results from Apollo 16 and 17

Exposure ages of Apollo 17 rocks as measured by tracks and the Kr-Kr rare gas method are reported. Concordant ages of 22 - or + 1 million year (my) are obtained for the station 6 boulder sample 76315. This value is interpreted as the time when the station 6 boulder was emplaced in its present position. Reasonable agreement is also obtained by the two methods for another station 6 boulder, sample 76015. Discordant ages (respectively 5 and 28 my by the track and rare gas methods) are obtained for the station 7 boulder sample, 77135, indicating that the boulder was emplaced at least 5 my ago. The 72 my exposure age of 75035, in general agreement with previous measurements of approximately 85 my for another Camelot boulder, may well date the formation of Camelot. Rock 76015 was split and one surface exposed to the sky through a very small solid angle

Analysis Tools for Discovering Strong Parity Violation at Hadron Colliders

Several arguments suggest parity violation may be observable in high energy strong interactions. We introduce new analysis tools for describing the azimuthal dependence of multi-particle distributions, or "azimuthal flow." Analysis uses the representations of the orthogonal group O(2) and dihedral groups $D_{N}$ necessary to define parity correctly in two dimensions. Classification finds that collective angles used in event-by-event statistics represent inequivalent tensor observables that cannot generally be represented by a single "reaction plane". Many new parity-violating observables exist that have never been measured, while many new parity-conserving observables formerly lumped together are now distinguished. We use the concept of "event shape sorting" to suggest separating right- and left-handed events, and we discuss the effects of transverse and longitudinal spin. The analysis tools are statistically robust, and can be applied equally to low or high multiplicity events at the Tevatron, $RHIC$ or $RHIC\, Spin$, and the $LHC$.Comment: 18 pages, 2 figures. Final version, accepted for publication in PRD. Updated references. Modified presentation and discussion of previous wor

Electrochemical Evaluation of Constituent Intermetallics in Aluminum Alloy 2024-T3 Exposed to Aqueous Vanadate Inhibitors

Experiments were conducted to determine how inhibiting forms of vanadate interact with complex Al alloy microconstituent intermetallics to impart corrosion protection. Cathodic polarization experiments on Al 2024-T3 indicate a strong correlation between inhibition and the presence of tetrahedrally coordinated vanadate. Anodic and cathodic polarization curves were measured on bulk synthesized Al_2Cu, Al_2CuMg, Al_7Cu_2Fe, and Al_20Cu_2Mn_3 in alkaline 0.5 M NaCl solutions with and without 10 mM NaVO_3. Vanadate additions generally decreased E_corr, increased E_pit, and decreased the cathodic kinetics of all tested materials. Because of decreased cathodic kinetics, open-circuit potentials (OCPs) were shifted in the active direction in aerated solutions when vanadate was present. This shift pins the OCP just below the observed pitting potential for Al_2CuMg in vanadate solution, effectively preventing breakdown and subsequent support of rapid oxygen reduction by Cu-enriched clusters. E_corr, E_pit, E_rp, i_corr, i_pass, and i at −1.3 V_SCE data from polarization experiments were summarized in cumulative distribution plots, and averages are presented in tabulated format. Scanning electron microscopy images of Al 2024-T3 used for 4 h of OCP measurement show that vanadate greatly decreased circumferential trenching around intermetallic particles in both aerated and deaerated solutions. Potentiostatic hold experiments were used to show suppression of Al_2CuMg dissolution in vanadate solutions

Corrosion Inhibition of Aluminum Alloy 2024-T3 by Aqueous Vanadium Species

Nuclear magnetic resonance (NMR) measurements were made on aqueous vanadate solutions to characterize speciation as a function of pH and vanadate concentration. Additionally, potentiodynamic polarization measurements were carried out on Al alloy 2024-T3 in 50 mM NaCl solutions in which pH and vanadate concentration were systematically varied. Results showed that inhibition by vanadates occurred mainly in alkaline solutions where tetrahedrally coordinated vanadates, metavanadate and pyrovanadate, were abundant. Inhibition was not observed in solutions where octahedrally coordinated decavanadates predominated. Anodic inhibition, in the form of increased pitting potential, was observed in both aerated and deaerated solutions. In contrast, cathodic inhibition was observed only in aerated solutions acting primarily through the suppression of oxygen reduction. Energy-dispersive spectroscopy, used to collect chemical maps from aluminum coupons exposed to vanadate solutions, showed the suppression of Al_2CuMg particle dissolution compared to vanadate-free solutions. NMR measurements were also used to track changes in vanadate speciation with time, pH adjustment, and with exposure to metallic aluminum surfaces. NMR showed noninhibiting octahedrally coordinated decavanadates rapidly decompose into inhibiting tetrahedrally coordinated metavanadates and pyrovanadates after alkaline pH adjustment. While decomposition begins immediately upon pH adjustment, equilibrium may not be reached even after significant time periods

Indication of Anisotropy in Electromagnetic Propagation over Cosmological Distances

We report a systematic rotation of the plane of polarization of electromagnetic radiation propagating over cosmological distances. The effect is extracted independently from Faraday rotation, and found to be correlated with the angular positions and distances to the sources. Monte Carlo analysis yields probabilistic P-values of order 10^(-3) for this to occur as a fluctuation. A fit yields a birefringence scale of order 10^(25) meters. Dependence on redshift z rules out a local effect. Barring hidden systematic bias in the data, the correlation indicates a new cosmological effect.Comment: 5 pages, 1 figure, ReVTeX. For more information, see http://www.cc.rochester.edu/college/rtc/Borge/aniso.htm

Photon Generalized Parton Distributions

We present a calculation of the generalized parton distributions of the photon using overlaps of photon light-front wave functions.Comment: Talk given at LightCone 2011, 4 pages, 3 figure

Exclusive Hadronic Processes and Color Transparency

We review the current status of high energy exclusive processes and color transparency.Comment: 17 pages, 8 figures, based on talk given at International Symposium on Nuclear Physics, Mumbai, Dec 18-22, 200

Connection between the elastic GEp/GMp and P to Delta form factors

It is suggested that the falloff in Qsq of the P to Delta magnetic form factor GM* is related to the recently observed falloff of the elastic electric form factor GEp/GMp. Calculation is carried out in the framework of a GPD mechanism