Black Symposium_Correspondence between Stephen Hughes and Rhody McCoy on Participating in Symposium on Black America

A letter from University faculty member Stephen Hughes, written on January 8, 1969 to Rhody McCoy, Unit Administrator of Ocean Hill-Brownsville Demonstration School District in Brooklyn New York, to participate in the Symposium on Black America. Rhody McCoy responded on January 15, 1969 accepting the invitation to speak at the Symposium. After the Symposium Stephen Hughes wrote to Rhody McCoy on February 24, 1969 to give thanks for participating in the Symposium and included a check of payment. The last page is a poster created to showcase Rhody McCoy\u27s talk at the University on Monday February 17 at Eight PM in 137 Bennett Hall continuing the series of the Symposium on Black America.https://digitalcommons.library.umaine.edu/racial_justice/1015/thumbnail.jp

Black Symposium Correspondence between Stephen Hughes and Rhody McCoy on Participating in Symposium on Black America

A letter from University faculty member Stephen Hughes, written on January 8, 1969 to Rhody McCoy, Unit Administrator of Ocean Hill-Brownsville Demonstration School District in Brooklyn New York, to participate in the Symposium on Black America. Rhody McCoy responded on January 15, 1969 accepting the invitation to speak at the Symposium. After the Symposium Stephen Hughes wrote to Rhody McCoy on February 24, 1969 to give thanks for participating in the Symposium and included a check of payment. The last page is a poster created to showcase Rhody McCoy\u27s talk at the University on Monday February 17 at Eight PM in 137 Bennett Hall continuing the series of the Symposium on Black America

Exact solution of a 2d random Ising model

The model considered is a d=2 layered random Ising system on a square lattice with nearest neighbours interaction. It is assumed that all the vertical couplings are equal and take the positive value J while the horizontal couplings are quenched random variables which are equal in the same row but can take the two possible values J and J-K in different rows. The exact solution is obtained in the limit case of infinite K for any distribution of the horizontal couplings. The model which corresponds to this limit can be seen as an ordinary Ising system where the spins of some rows, chosen at random, are frozen in an antiferromagnetic order. No phase transition is found if the horizontal couplings are independent random variables while for correlated disorder one finds a low temperature phase with some glassy properties.Comment: 10 pages, Plain TeX, 3 ps figures, submitted to Europhys. Let

Development of boldness and docility in yellow-bellied marmots

Peer reviewedPostprin

Zero--Temperature Quantum Phase Transition of a Two--Dimensional Ising Spin--Glass

We study the quantum transition at $T=0$ in the spin-$\frac12$ Ising spin--glass in a transverse field in two dimensions. The world line path integral representation of this model corresponds to an effective classical system in (2+1) dimensions, which we study by Monte Carlo simulations. Values of the critical exponents are estimated by a finite-size scaling analysis. We find that the dynamical exponent, $z$, and the correlation length exponent, $\nu$, are given by $z = 1.5 \pm 0.05$ and $\nu = 1.0 \pm 0.1$. Both the linear and non-linear susceptibility are found to diverge at the critical point.Comment: RevTeX 10 pages + 4 figures (appended as uuencoded, compressed tar-file), THP21-9

Lifecycle CO2 emissions from US bioethanol production with CCS

There is growing consensus that carbon dioxide removal (CDR) technologies – also referred to as “negative emissions” technologies (NETs) – will be part of the portfolio of strategies and technologies needed to hold the increase in the global average temperature to “well below 2 °C” (1), as agreed by parties to the Paris Agreement. The production of bioenergy with carbon capture and sequestration (BECCS) is one class of CDR technology (2), involving the capture and geologic storage of CO2 (CCS) that would otherwise be emitted to the atmosphere from use of biomass as a fuel for electricity generation or feedstock for production of liquid fuels. Use of CCS typically imposes two energy penalties that can diminish its benefits: energy is needed to separate CO2 from dilute CO2-containing mixtures (e.g. flue gas), and to liquefy CO2 so that it can be transported and injected into geologic formations. The predominant biofuel production pathway in the United States (U.S.) today is conversion of corn starch to ethanol, which generates relatively high-concentration CO2 from fermentation and dilute-CO2 from fuel combustion for process heat. In 2015, the U.S. produced approximately 53 billion liters of bioethanol from nearly 200 facilities (3) releasing approximately 40 MtCO2 of CO2 from fermentation and a further 20 MtCO2 from process heat (4). The climate benefit of applying CCS to biofuel production – and BECCS more generally – can only be accurately assessed in the context of emissions over the entire fuel production pathway, including the biomass supply chain. Few prior studies have quantified the carbon intensity of biofuels, such as ethanol, produced from processes including CCS (5–8). While previous studies consider a range of feedstocks (i.e., sugar cane, beets, and corn), none consider the emissions from direct and indirect land-use change associated with feedstock production and some use dated assumptions for key parameters, such as corn and ethanol yields (7,8). However, all conclude that, with the addition of CCS, GHG intensity of produced fuels decreases and can become negative (even without credit for displacement). In this paper, we quantify the life-cycle emissions of several corn-ethanol production pathways coupled with CCS at different process steps. Specifically, we assess the lifecycle emissions for dry-mill ethanol production with and without CCS for fermentation process emissions and for onsite boiler or cogeneration emissions. We run these scenarios for representative U.S. corn ethanol plants, and include recent estimates of indirect land use change. Finally, we do a detailed parametric sensitivity analysis of our results. 1. Sanderson BM, O’Neill BC, Tebaldi C. What would it take to achieve the Paris temperature targets? Geophys Res Lett. 2016 Jul 16;43(13):7133–42. 2. The Royal Society. Geoengineering the climate: science, governance and uncertainty [Internet]. London, UK: The Royal Society; 2009. Available from: https://royalsociety.org/topics- policy/publications/2009/geoengineering-climate/ 3. U.S. DOE. Renewable & Alternative Fuels - Data [Internet]. U.S. Energy Information Administration (EIA). [cited 2017 Jan 14]. Available from: http://www.eia.gov/renewable/data.cfm#alternative 4. U.S. EPA. EPA Facility Level GHG Emissions Data [Internet]. [cited 2017 Jan 14]. Available from: https://ghgdata.epa.gov/ghgp/main.do 5. Lindfeldt EG, Westermark MO. System study of carbon dioxide (CO2) capture in bio-based motor fuel production. 19th Int Conf Effic Cost Optim Simul Environ Impactof Energy Syst 2006. 2008 Feb;33(2):352–61. 6. Laude A, Ricci O, Bureau G, Royer-Adnot J, Fabbri A. CO2 capture and storage from a bioethanol plant: Carbon and energy footprint and economic assessment. Int J Greenh Gas Control. 2011;5(5):1220–31. 7. Möllersten K, Yan J, R. Moreira J. Potential market niches for biomass energy with CO2 capture and storage--Opportunities for energy supply with negative CO2 emissions. Biomass Bioenergy. 2003;25(3):273–85. 8. Kheshgi HS, Prince RC. Sequestration of fermentation CO2 from ethanol production. Energy. 2005 Jul;30(10):1865–71

Structure analysis of the Ga-stabilized GaAs(001)-c(8x2) surface at high temperatures

Structure of the Ga-stabilized GaAs(001)-c(8x2) surface has been studied using rocking-curve analysis of reflection high-energy electron diffraction (RHEED). The c(8x2) structure emerges at temperatures higher than 600C, but is unstable with respect to the change to the (2x6)/(3x6) structure at lower temperatures. Our RHEED rocking-curve analysis at high temperatures revealed that the c(8x2) surface has the structure which is basically the same as that recently proposed by Kumpf et al. [Phys. Rev. Lett. 86, 3586 (2001)]. We found that the surface atomic configurations are locally fluctuated at high temperatures without disturbing the c(8x2) periodicity.Comment: 14 pages, 4 figures, 1 tabl

Griffiths-McCoy Singularities in the Random Transverse-Field Ising Spin Chain

We consider the paramagnetic phase of the random transverse-field Ising spin chain and study the dynamical properties by numerical methods and scaling considerations. We extend our previous work [Phys. Rev. B 57, 11404 (1998)] to new quantities, such as the non-linear susceptibility, higher excitations and the energy-density autocorrelation function. We show that in the Griffiths phase all the above quantities exhibit power-law singularities and the corresponding critical exponents, which vary with the distance from the critical point, can be related to the dynamical exponent z, the latter being the positive root of [(J/h)^{1/z}]_av=1. Particularly, whereas the average spin autocorrelation function in imaginary time decays as [G]_av(t)~t^{-1/z}, the average energy-density autocorrelations decay with another exponent as [G^e]_av(t)~t^{-2-1/z}.Comment: 8 pages RevTeX, 8 eps-figures include