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Lancaster, PA, United States

Haverford College is a private, coeducational liberal arts college located in Haverford, Pennsylvania, United States, a suburb of Philadelphia. All students of the College are undergraduates, and nearly all reside on campus.The college was founded in 1833 by area members of the Orthodox Philadelphia Yearly Meeting of the Religious Society of Friends to ensure an education grounded in Quaker values for young Quaker men. Although the college no longer has a formal religious affiliation, the Quaker philosophy still influences campus life. Originally an all-male institution, Haverford began admitting female transfer students in the 1970s and became fully co-ed in 1980. Currently, more than half of Haverford's students are women. For most of the 20th century, Haverford's total enrollment was kept below 300, but the school went through two periods of expansion after the 1970s, and its current enrollment is 1,190 students. As of the 2012–2013 academic year, Haverford College's tuition is $43,310; room and board, $13,290; activity fee, $392; and orientation fee, $210. This amounts to a total of $57,202.Haverford is a member of the Tri-College Consortium, which allows students to register for courses at both Bryn Mawr College and Swarthmore College. The college engages in an especially close relationship with Bryn Mawr College. It is also a member of the Quaker Consortium which allows students to cross-register at the College of General Studies and the Wharton School of Business at the University of Pennsylvania. The college was ranked 11th among all colleges and universities in the 2014 edition of Forbes' "Top Colleges", and 9th among national liberal arts colleges by the 2013 edition of U.S. News and World Report. A 2012 Forbes ranking on the colleges which produce the most entrepreneurs per capita placed Haverford first among liberal arts colleges and tenth overall . Wikipedia.


Schrier J.,Haverford College
Solar Energy | Year: 2012

Production of fuel-grade ethanol requires removing excess water following fermentation, which is typically performed by an energy intensive distillation process. This paper proposes a simple, low-cost, and scalable alternative method of removing water using forward osmosis. The draw solution is an aqueous brine that is regenerated by solar evaporation. Separation limits of this approach are calculated using the van Laar equation for the non-ideality of the ethanol/water mixture, and experimentally measured activities for aqueous solutions of NaCl, CaCl 2, K 2HPO 4, and K 4P 2O 7. We focus on production of 95%, 50% and 30% (w/w) ethanol solutions as fuel for cooking stoves and homogeneous charge compression ignition (HCCI) engines, both of which tolerate larger amounts of water in the product. Evaporation-limited production rates are computed using long-term meteorological data for sites in Ethiopia, Thailand, Brazil, and India. These calculations can be used to determine the size requirements necessary for a given daily production rate for any desired ethanol concentration. © 2012 Elsevier Ltd. Source


Willman B.,Haverford College | Strader J.,Harvard - Smithsonian Center for Astrophysics
Astronomical Journal | Year: 2012

A growing number of low luminosity and low surface brightness astronomical objects challenge traditional notions of both galaxies and star clusters. To address this challenge, we propose a definition of galaxy that does not depend on a cold dark matter model of the universe: a galaxy is a gravitationally bound collection of stars whose properties cannot be explained by a combination of baryons and Newton's laws of gravity. After exploring several possible observational diagnostics of this definition, we critically examine the classification of ultra-faint dwarfs, globular clusters, ultra-compact dwarfs, and tidal dwarfs. While kinematic studies provide an effective diagnostic of the definition in many regimes, they can be less useful for compact or very faint systems. To explore the utility of using the [Fe/H] spread as a complementary diagnostic, we use published spectroscopic [Fe/H] measurements of 16 Milky Way dwarfs and 24 globular clusters to uniformly calculate their [Fe/H] spreads and associated uncertainties. Our principal results are (1) no known, old star cluster less luminous than M V = -10 has a significant (≳0.1 dex) spread in its iron abundance; (2) known ultra-faint dwarf galaxies can be unambiguously classified with a combination of kinematic and [Fe/H] observations; (3) the observed [Fe/H] spreads in massive (≳ 10 6 M ⊙) globular clusters do not necessarily imply that they are the stripped nuclei of dwarfs, nor a need for dark matter; and (4) if ultra-compact dwarf galaxies reside in dark matter halos akin to those of ultra-faint dwarfs of the same half-light radii, then they will show no clear dynamical signature of dark matter. We suggest several measurements that may assist the future classification of massive globular clusters, ultra-compact dwarfs, and ultra-faint galaxies. Our galaxy definition is designed to be independent of the details of current observations and models, while our proposed diagnostics can be refined or replaced as our understanding of the universe evolves. © © 2012. The American Astronomical Society. All rights reserved. Source


Wilson J.P.,Haverford College
Review of Palaeobotany and Palynology | Year: 2016

Mathematical models of fluid flow through and embolism resistance of extinct plant xylem provide insight into the ecology and physiology of individual fossil plants. Disparate lineages of vascular plants exhibit a variety of ecophysiological strategies: extreme adaptations for maximum flow and maximum safety have both been documented in living and extinct plants. Analysis of early-diverging vascular plants and early-diverging seed plants shows that a variety of hydraulic strategies were pursued early in the evolution of terrestrial plants, especially during the Devonian and Carboniferous Periods. Analysis of five species of the Lower and Middle Devonian trimerophyte genus Psilophyton indicates that some species possess low-resistance metaxylem tracheids with numerous, highly porous pits and relatively low embolism resistance, whereas other species contain xylem with higher embolism resistance and lower hydraulic conductivity. Despite a simple vegetative morphology, physiological analysis of several Psilophyton fossils suggests that species possessed distinct ecophysiological strategies and there may be cryptic functional diversity within other trimerophyte genera. When integrated with previous hydraulic analyses of extinct and extant plants, including the Lower Devonian stem group lycophyte Asteroxylon mackiei; a series of Carboniferous stem group seed plants, including Medullosa, Callistophyton, and Lyginopteris; eleven genera of extant conifers and cycads; two species of ginkgophytes, and others, the occupation of tracheid-based hydraulic ecospace can be mapped. Soon after the evolution of vascular tissue in land plants, the high-conductivity/low-safety-margin space was occupied; particularly by plants that grew in the tropical lowland swamps during the Carboniferous Period. Upon the disappearance of the coal swamp floras during the Permian Period, that portion of the ecospace may have remained unoccupied until the evolution of angiosperms with vessels in the Cretaceous Period. Taken as a whole, the evolution of vascular tissue during (and after) the terrestrialization process records several physiological adaptive radiations, occurring early in plant evolution, which likely had major effects on global environmental and biogeochemical processes. © 2016 Elsevier B.V. Source


Schrier J.,Haverford College
ACS Applied Materials and Interfaces | Year: 2012

Carbon dioxide gas separation is important for many environmental and energy applications. Molecular dynamics simulations are used to characterize a two-dimensional hydrocarbon polymer, PG-ES1, that uses a combination of surface adsorption and narrow pores to separate carbon dioxide from nitrogen, oxygen, and methane gases. The CO 2 permeance is 3 × 10 5 gas permeation units (GPU). The CO 2/N 2 selectivity is 60, and the CO 2/CH 4 selectivity exceeds 500. The combination of high CO 2 permeance and selectivity surpasses all known materials, enabling low-cost postcombustion CO 2 capture, utilization of landfill gas, and horticulture applications. © 2012 American Chemical Society. Source


Casey C.M.,University of California at Irvine | Casey C.M.,University of Hawaii at Manoa | Narayanan D.,Haverford College | Cooray A.,University of California at Irvine
Physics Reports | Year: 2014

Far-infrared and submillimeter wavelength surveys have now established the important role of dusty, star-forming galaxies (DSFGs) in the assembly of stellar mass and the evolution of massive galaxies in the Universe. The brightest of these galaxies have infrared luminosities in excess of 1013L⊙ with implied star-formation rates of thousands of solar masses per year. They represent the most intense starbursts in the Universe, yet many are completely optically obscured. Their easy detection at submm wavelengths is due to dust heated by ultraviolet radiation of newly forming stars. When summed up, all of the dusty, star-forming galaxies in the Universe produce an infrared radiation field that has an equal energy density as the direct starlight emission from all galaxies visible at ultraviolet and optical wavelengths. The bulk of this infrared extragalactic background light emanates from galaxies as diverse as gas-rich disks to mergers of intense starbursting galaxies. Major advances in far-infrared instrumentation in recent years, both space-based and ground-based, has led to the detection of nearly a million DSFGs, yet our understanding of the underlying astrophysics that govern the start and end of the dusty starburst phase is still in nascent stage. This review is aimed at summarizing the current status of DSFG studies, focusing especially on the detailed characterization of the best-understood subset (submillimeter galaxies, who were summarized in the last review of this field over a decade ago, Blain et al., 2002), but also the selection and characterization of more recently discovered DSFG populations. We review DSFG population statistics, their physical properties including dust, gas and stellar contents, their environments, and current theoretical models related to the formation and evolution of these galaxies. © 2014 Elsevier B.V. Source

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