Metastability of a granular surface in a spinning bucket

The surface shape of a spinning bucket of granular material is studied using a continuum model of surface flow developed by Bouchaud et al. and Mehta et al. An experimentally observed central subcritical region is reproduced by the model. The subcritical region occurs when a metastable surface becomes unstable via a nonlinear instability mechanism. The nonlinear instability mechanism destabilizes the surface in large systems while a linear instability mechanism is relevant for smaller systems. The range of angles in which the granular surface is metastable vanishes with increasing system size.Comment: 8 pages with postscript figures, RevTex, to appear in Phys. Rev.

Dual Action Additives for Jet A-1: Fuel Dehydrating Icing Inhibitors

© 2016 American Chemical Society. A novel approach for protecting jet fuel against the effects of water contamination based upon Fuel Dehydrating Icing Inhibitors (FDII) is presented. This dual-action strategy is predicated on the addition of a fuel-soluble water scavenger that undergoes a kinetically fast hydrolysis reaction with free water to produce a hydrophilic ice inhibitor, thereby further militating against the effects of water crystallization. Criteria for an optimum FDII were identified and then used to screen a range of potential water-scavenging agents, which led to a closer examination of systems based upon exo/endo-cyclic ketals and both endo- and exo-cyclic ortho esters. The ice inhibition properties of the subsequent products of the hydrolysis reaction in Jet A-1 were screened by differential scanning calorimetry. The hydrolysis products of 2-methoxy-2-methyl-1,3-dioxolane demonstrate similar ice inhibition performance to DiEGME over a range of blend levels. The calorific values for the products of hydrolysis were also investigated, and it is clear that there would be a significant fuel saving on use of the additive over current fuel system icing inhibitors. Finally, three promising candidates, 2-methoxy-2-methyl-1,3-dioxolane, 2-methoxy-2-methyl-1,3-dioxane, and 2-methoxy-2,4,5-trimethyl-1,3-dioxolane, were shown to effectively dehydrate Jet A-1 at room temperature over a 2 h period

The Grizzly, February 5, 1982

Wismer Thefts Provoke Action • Lloyd\u27s Tenure Rejection Official • KDK Attains Highest GPA • Rod Luck Visits W\u27s Gymnastics • Comment: New Faculty Program a Contradiction of Goals? • On Energy Conservation • Administration\u27s Views on Pledging • Book Store Improves Under New Management • Bell Rate Hikes to Affect Students • Pattern Changes Planned for Next Semester • The Way to a Man\u27s Heart • Japanese Program Opens This Summer • Aquamen Swamp E-town • Racqueteers Rolling • Women Splash to Victory • Sterling Brown to Take Over Football Team • B-Ball Takes Two • Girls Dump Mighty Macshttps://digitalcommons.ursinus.edu/grizzlynews/1071/thumbnail.jp

TEMPRANILLO is a regulator of juvenility in plants

Many plants are incapable of flowering in inductive daylengths during the early juvenile vegetative phase (JVP). Arabidopsis mutants with reduced expression of TEMPRANILLO (TEM), a repressor of FLOWERING LOCUS T (FT) had a shorter JVP than wild-type plants. Reciprocal changes in mRNA expression of TEM and FT were observed in both Arabidopsis and antirrhinum, which correlated with the length of the JVP. FT expression was induced just prior to the end of the JVP and levels of TEM1 mRNA declined rapidly at the time when FT mRNA levels were shown to increase. TEM orthologs were isolated from antirrhinum (AmTEM) and olive (OeTEM) and were expressed most highly during their juvenile phase. AmTEM functionally complemented AtTEM1 in the tem1 mutant and over-expression of AmTEM prolonged the JVP through repression of FT and CONSTANS (CO). We propose that TEM may have a general role in regulating JVP in herbaceous and woody species

The Grizzly, January 29, 1982

Two Alumni Join Administration • So Much, POD, in College Bowl Finals • Hermann Eilts on The Middle East • College Receives $500,000 • Teachers Audition For EC/BA Positions • Honor Societies Meet to Discuss Future Plans • Union Undergoes Attractive Renovations • Evening School Expands • Spiritwood Returns for Coffeehouse • German Students Sample American College Life • Mozart Concert to Conclude Winterfest! • Myrin Exhibits Storybook Etchings • Collegeville Claustrophobia? • Schaff Plagued With Repeated Break-ins • Forums, Forums, Forums • Mens Basketball Has Good Vacation • Gymnasts\u27 Work Pays Off • Badminton Opens Season With Temple • Grapplers Impressive in Latest Victories • Hoopsters Lose to Widener • Karas Resigns; New Coach Expected Soon • Widener Drownshttps://digitalcommons.ursinus.edu/grizzlynews/1070/thumbnail.jp

Improving electrocoagulation floatation for harvesting microalgae

Electro-coagulation floatation (ECF) is a foam-floatation dewatering method that has been shown to be a highly effective, rapid, and scalable separation methodology. In this manuscript, an in-depth analysis of the gas and flocculant levels observed during the process is provided, with microbubbles observed in the 5–80μm size range at a concentration of 102–103 bubbles mL−1. Electrolysis of microalgae culture was then observed, demonstrating both effective separation using aluminium electrodes (nine microalgal species tested, 1–40μm size range, motile and non-motile, marine and freshwater), and sterilisation of culture through bleaching with inert titanium electrodes. Atomic force microscopy was used to visualise floc formation in the presence and absence of algae, showing nanoscale structures on the magnitude of 40–400nm and entrapped microalgal cells. Improvements to aid industrial biotechnology processing were investigated: protein-doping was found to improve foam stability without inducing cell lysis, and an oxalate buffer wash regime was found to dissolve the flocculant whilst producing no observable difference in the final algal lipid or pigment profiles, leaving the cells viable at the end of the process. ECF separated microalgal culture had an algal biomass loading of 13% and as such wasideal for direct down-stream processing through hydrothermal liquefaction. Highbio-crude yieldswere achieved, though this was reduced slightly on addition of the Al(OH)3 after ECF, with carbon being distributed away to the aqueous and solid residue phases. The amenability and compatibility of ECF to integration with, or replacement of, existing centrifugation and settling processes suggests this process may be of significant interest to the biotechnology industry

Bacterial Killing Via A Type Iv Secretion System.

Type IV secretion systems (T4SSs) are multiprotein complexes that transport effector proteins and protein-DNA complexes through bacterial membranes to the extracellular milieu or directly into the cytoplasm of other cells. Many bacteria of the family Xanthomonadaceae, which occupy diverse environmental niches, carry a T4SS with unknown function but with several characteristics that distinguishes it from other T4SSs. Here we show that the Xanthomonas citri T4SS provides these cells the capacity to kill other Gram-negative bacterial species in a contact-dependent manner. The secretion of one type IV bacterial effector protein is shown to require a conserved C-terminal domain and its bacteriolytic activity is neutralized by a cognate immunity protein whose 3D structure is similar to peptidoglycan hydrolase inhibitors. This is the first demonstration of the involvement of a T4SS in bacterial killing and points to this special class of T4SS as a mediator of both antagonistic and cooperative interbacterial interactions.6645

Reverberation Mapping of the Kepler-Field AGN KA1858+4850

KA1858+4850 is a narrow-line Seyfert 1 galaxy at redshift 0.078 and is among the brightest active galaxies monitored by the Kepler mission. We have carried out a reverberation mapping campaign designed to measure the broad-line region size and estimate the mass of the black hole in this galaxy. We obtained 74 epochs of spectroscopic data using the Kast Spectrograph at the Lick 3-m telescope from February to November of 2012, and obtained complementary V-band images from five other ground-based telescopes. We measured the H-beta light curve lag with respect to the V-band continuum light curve using both cross-correlation techniques (CCF) and continuum light curve variability modeling with the JAVELIN method, and found rest-frame lags of lag_CCF = 13.53 (+2.03, -2.32) days and lag_JAVELIN = 13.15 (+1.08, -1.00) days. The H-beta root-mean-square line profile has a width of sigma_line = 770 +/- 49 km/s. Combining these two results and assuming a virial scale factor of f = 5.13, we obtained a virial estimate of M_BH = 8.06 (+1.59, -1.72) x 10^6 M_sun for the mass of the central black hole and an Eddington ratio of L/L_Edd ~ 0.2. We also obtained consistent but slightly shorter emission-line lags with respect to the Kepler light curve. Thanks to the Kepler mission, the light curve of KA1858+4850 has among the highest cadences and signal-to-noise ratios ever measured for an active galactic nucleus; thus, our black hole mass measurement will serve as a reference point for relations between black hole mass and continuum variability characteristics in active galactic nuclei

Detectors for the James Webb Space Telescope Near-Infrared Spectrograph I: Readout Mode, Noise Model, and Calibration Considerations

We describe how the James Webb Space Telescope (JWST) Near-Infrared Spectrograph's (NIRSpec's) detectors will be read out, and present a model of how noise scales with the number of multiple non-destructive reads sampling-up-the-ramp. We believe that this noise model, which is validated using real and simulated test data, is applicable to most astronomical near-infrared instruments. We describe some non-ideal behaviors that have been observed in engineering grade NIRSpec detectors, and demonstrate that they are unlikely to affect NIRSpec sensitivity, operations, or calibration. These include a HAWAII-2RG reset anomaly and random telegraph noise (RTN). Using real test data, we show that the reset anomaly is: (1) very nearly noiseless and (2) can be easily calibrated out. Likewise, we show that large-amplitude RTN affects only a small and fixed population of pixels. It can therefore be tracked using standard pixel operability maps.Comment: 55 pages, 10 figure

The Grizzly, February 19, 1982

Union Victim of Apparent Vandalism • Bomberger to be Closed After Hours if Vandalism Continues • Foreign Language Career Day: Getting an Edge in Business • Arnold to Join Administration • Reagan: Friend of the Forces • Richter Urges Campus Involvement • Parents Notified of Possible Changes in Aid • Fraternities and Presidents • Meistersingers Begin Spring Concert Tour • English Department Considers Changes • News Briefs: Astronomer to Speak at Ursinus College; Winning Photographer to Conduct Courses at Ursinus College • Joan Jett at the Tower: I Don\u27t Care About a Bad Reputation • Winterfest 1982 • Pi Nu Epsilon: New Members Honored • UC Represents Bahrain in Model UN • USGA Notes • Aggies Buried by UC Women • Women Lose Thriller • Women\u27s Badminton • Sports Briefs: Aquabears Drop One to F&M; Men\u27s Intramural B-ball; Gymnasts Vault to Best Scores • Men\u27s Hoops Takes Two Out of Three • Grapplers Record Best in UC Historyhttps://digitalcommons.ursinus.edu/grizzlynews/1073/thumbnail.jp