Investigation of clay smear formation in laboratory-prepared layered soil specimens

The purpose of this study was to investigate the impact of layering geometry on the formation of clay smears in laboratory prepared soil specimens. Digitized video clips of specimen deformation under vertical shear were reviewed. New conventions and definitions were developed to describe and measure the onset of clay smear. Measurements for a variety of sample layering geometries were taken. Specimen geometry was compared with its respective smear development properties to derive general relationships; The study showed that as the sand thickness within a specimen increased, the required amount of vertical displacement and sand layer displacement prior to smear also increased. Ratios of sand to clay within a specimen did not alone provide a consistent indicator on the development of smear. However, by normalizing the sand layer displacement required for smear, a nearly constant value for all samples was achieved

Electrochemical Characterization of Precious Metal Braze Alloys Using Potentiodynamic Polarization

This study aimed to characterize the electrochemical behavior of six precious metal braze alloys by performing potentiodynamic polarization tests (ParStat 2273) based on ASTM Specifications G5 and G59. To determine the extent to which the alloys will contribute to galvanic corrosion in a marine environment (3.5 wt% NaCl), corrosion analysis software was used to produce fitted Tafel lines to determine the open circuit potential, Voc, for each alloy. The Voc values for the alloys were found to be -66.58 mV for Gold ABA, 13.01 mV for Nicoro®, -39.00 mV for Nioro®, 23.4 mV for Palniro-1®, -47.91 mV for Palniro-7®, and -205.16 mV for Silver ABA. These values were compared to industry-standard base materials typically used in brazing processes to determine their compatibility as galvanic couples. Differences in Voc greater than 250 mV within the couple are considered unsuitable for joining without additional galvanic protection. To provide coupling recommendations, 95% confidence intervals were made to estimate each alloy’s Voc

Koinonia

Conference SpotlightFrom Ordinary to Extraordinary, John Maxwell Leadership DevelopmentEPIC Leadership: Preparing EPIC Leaders Using Images, Experiences, and Relationship, Tim Elmore Diversity & CommunityDiversity in Evangelical Higher Education: An Interview with Will Kratt, Glen Kinoshita Sophomore Community Groups, Andrew Shriver Thinking Theologically: Considering Community-Part 1, Todd Ream Book ReviewsA History of American Higher Education, reviewed by Jerry Schwenke Hurt: Inside the World of Today\u27s Teenagers, reviewed by Brie McDaniel ReflectionsSnapshots from ACSD 2005 FeaturesThe President\u27s Corner Editor\u27s Diskhttps://pillars.taylor.edu/acsd_koinonia/1005/thumbnail.jp

Geometric distortion calibration with photolithographic pinhole masks for high-precision astrometry

Adaptive optics (AO) systems deliver high-resolution images that may be ideal for precisely measuring positions of stars (i.e., astrometry) if the system has stable and well-calibrated geometric optical distortions. A calibration unit equipped with a back-illuminated pinhole mask can be utilized to measure instrumental optical distortions. AO systems on the largest ground-based telescopes, such as the W. M. Keck Observatory and the Thirty Meter Telescope (TMT), require pinhole positions known to be ∼20  nm to achieve an astrometric precision of 0.001 of a resolution element. In pursuit of that goal, we characterize a photolithographic pinhole mask and explore the systematic errors that result from different experimental setups. We characterized the nonlinear geometric distortion of a simple imaging system using the mask, and we measured 857-nm root mean square of optical distortion with a final residual of 39 nm (equivalent to 20  μ for TMT). We use a sixth-order bivariate Legendre polynomial to model the optical distortion and allow the reference positions of the individual pinholes to vary. The nonlinear deviations in the pinhole pattern with respect to the manufacturing design of a square pattern are 47.2 nm ± 4.5 nm (random) ± 10.8 nm (systematic) over an area of 1788  mm². These deviations reflect the additional error induced when assuming that the pinhole mask is manufactured perfectly square. We also find that ordered mask distortions are significantly more difficult to characterize than random mask distortions as the ordered distortions can alias into optical camera distortion. Future design simulations for astrometric calibration units should include ordered mask distortions. We conclude that photolithographic pinhole masks are >10 times better than the pinhole masks deployed in first-generation AO systems and are sufficient to meet the distortion calibration requirements for the upcoming 30-m-class telescopes

Mitochondria as a Target of Environmental Toxicants

Enormous strides have recently been made in our understanding of the biology and pathobiology of mitochondria. Many diseases have been identified as caused by mitochondrial dysfunction, and many pharmaceuticals have been identified as previously unrecognized mitochondrial toxicants. A much smaller but growing literature indicates that mitochondria are also targeted by environmental pollutants. We briefly review the importance of mitochondrial function and maintenance for health based on the genetics of mitochondrial diseases and the toxicities resulting from pharmaceutical exposure. We then discuss how the principles of mitochondrial vulnerability illustrated by those fields might apply to environmental contaminants, with particular attention to factors that may modulate vulnerability including genetic differences, epigenetic interactions, tissue characteristics, and developmental stage. Finally, we review the literature related to environmental mitochondrial toxicants, with a particular focus on those toxicants that target mitochondrial DNA. We conclude that the fields of environmental toxicology and environmental health should focus more strongly on mitochondri

Eruptions at Lone Star geyser, Yellowstone National Park, USA: 2. Constraints on subsurface dynamics

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 119 (2014): 8688–8707, doi:10.1002/2014JB011526.We use seismic, tilt, lidar, thermal, and gravity data from 32 consecutive eruption cycles of Lone Star geyser in Yellowstone National Park to identify key subsurface processes throughout the geyser's eruption cycle. Previously, we described measurements and analyses associated with the geyser's erupting jet dynamics. Here we show that seismicity is dominated by hydrothermal tremor (~5–40 Hz) attributed to the nucleation and/or collapse of vapor bubbles. Water discharge during eruption preplay triggers high-amplitude tremor pulses from a back azimuth aligned with the geyser cone, but during the rest of the eruption cycle it is shifted to the east-northeast. Moreover, ~4 min period ground surface displacements recur every 26 ± 8 min and are uncorrelated with the eruption cycle. Based on these observations, we conclude that (1) the dynamical behavior of the geyser is controlled by the thermo-mechanical coupling between the geyser conduit and a laterally offset reservoir periodically filled with a highly compressible two-phase mixture, (2) liquid and steam slugs periodically ascend into the shallow crust near the geyser system inducing detectable deformation, (3) eruptions occur when the pressure decrease associated with overflow from geyser conduit during preplay triggers an unstable feedback between vapor generation (cavitation) and mass discharge, and (4) flow choking at a constriction in the conduit arrests the runaway process and increases the saturated vapor pressure in the reservoir by a factor of ~10 during eruptions.Funding for USGS team members was provided by the USGS Volcano Hazards Program. R. Sohn's participation was supported by the WHOI Green Technology Program. M. Manga, L. Karlstrom and M. Rudolph did receive salary from the National Science Foundation to spend time on this project.2015-06-0

Thermal Evolution of Compact Stars

A collection of modern, field-theoretical equations of state is applied to the investigation of cooling properties of compact stars. These comprise neutron stars as well as hypothetical strange matter stars, made up of absolutely stable 3-flavor strange quark matter. Various uncertainties in the behavior of matter at supernuclear densities, e.g., hyperonic degrees of freedom, behavior of coupling strengths in matter, pion and meson condensation, superfluidity, transition to quark matter, absolute stability of strange quark matter, and last but not least the many-body technique itself are tested against the body of observed cooling data.Comment: 41 pages, revised versio

Campaign Finance Reform: The Unfinished Agenda

In 1974, following the Watergate scandal, Congress enacted major campaign finance reform legislation. The legislation created a revolutionary new public financing system for our presidential campaigns, but it left congressional campaigns to be financed totally by private money. The presidential public financing system has worked well. Despite some incremental problems, the system has accomplished its basic goal of allowing individuals to run for the presidency without becoming dependent on their financial backers. The system for financing congressional cam paigns, on the other hand, is out of control and in need of fundamental reform. The inappropriate role of special interest political action commit tees (PACs) in influencing congressional elections and congressional decisions is the single biggest problem facing the political process. Congress needs to complete the unfinished campaign finance reform agenda of the 1970s by enacting public financing for congressional campaigns and establishing new restrictions on the total amount that PACs may give to a congressional candidate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67356/2/10.1177_000271628648600107.pd

Protocol for the development of guidance for stakeholder engagement in health and healthcare guideline development and implementation

Stakeholder engagement has become widely accepted as a necessary component of guideline development and implementation. While frameworks for developing guidelines express the need for those potentially affected by guideline recommendations to be involved in their development, there is a lack of consensus on how this should be done in practice. Further, there is a lack of guidance on how to equitably and meaningfully engage multiple stakeholders. We aim to develop guidance for the meaningful and equitable engagement of multiple stakeholders in guideline development and implementation. METHODS: This will be a multi-stage project. The first stage is to conduct a series of four systematic reviews. These will (1) describe existing guidance and methods for stakeholder engagement in guideline development and implementation, (2) characterize barriers and facilitators to stakeholder engagement in guideline development and implementation, (3) explore the impact of stakeholder engagement on guideline development and implementation, and (4) identify issues related to conflicts of interest when engaging multiple stakeholders in guideline development and implementation. DISCUSSION: We will collaborate with our multiple and diverse stakeholders to develop guidance for multi-stakeholder engagement in guideline development and implementation. We will use the results of the systematic reviews to develop a candidate list of draft guidance recommendations and will seek broad feedback on the draft guidance via an online survey of guideline developers and external stakeholders. An invited group of representatives from all stakeholder groups will discuss the results of the survey at a consensus meeting which will inform the development of the final guidance papers. Our overall goal is to improve the development of guidelines through meaningful and equitable multi-stakeholder engagement, and subsequently to improve health outcomes and reduce inequities in health