24,707 research outputs found
The Role of Disability Management Programs in ADA Compliance
This brochure on the role of disability management programs in American with Disabilities Act (ADA) compliance is one of a series on human resources practices and workplace accommodations for persons with disabilities edited by Susanne M. Bruyère, Ph.D., CRC, SPHR, Director, Program on Employment and Disability, School of Industrial and Labor Relations – Extension Division, Cornell University.
Cornell University was funded in the early 1990’s by the U.S. Department of Education National Institute on Disability and Rehabilitation Research as a National Materials Development Project on the employment provisions (Title I) of the ADA (Grant #H133D10155). These updates, and the development of new brochures, have been funded by Cornell’s Program on Employment and Disability, the Pacific Disability and Business Technical Assistance Center, and other supporters
A Generalization of Metropolis and Heat-Bath Sampling for Monte Carlo Simulations
For a wide class of applications of the Monte Carlo method, we describe a
general sampling methodology that is guaranteed to converge to a specified
equilibrium distribution function. The method is distinct from that of
Metropolis in that it is sometimes possible to arrange for unconditional
acceptance of trial moves. It involves sampling states in a local region of
phase space with probability equal to, in the first approximation, the square
root of the desired global probability density function. The validity of this
choice is derived from the Chapman-Kolmogorov equation, and the utility of the
method is illustrated by a prototypical numerical experiment.Comment: RevTeX, 7 pages, 2 table
Developing Offset Banking Systems in Georgia
Offset banking involves a public or private entity investing in a project that has the effect of substantially reducing a targeted pollutant(s), such as sediment runoff, phosphorus, heavy metals, etc. This project is referred to as "the bank." The entity creating the bank receives "credits" for the associated reduction in pollutants, which it can then sell to publically-owned treatment works (POTWs) or other point source polluters facing high costs of meeting discharge standards. Trades can be allowed on a 1-to-1 basis: the buyer obtains one credit for each creditequivalent increase in pollution associated with his/her activities; or higher trading ratios can be required, e.g., 3:1, where the buyer must acquire (in this example) three credits for each creditequivalent increase in pollution associated with his/her activities. In this latter case trades result in actual environmental improvements.This paper addresses two major issues. The first refers to the steps required to establish a pilot project for one or more offset banking projects in Georgia. These steps are: identifying entities with incentives to purchase offset credits; identifying one or more entities that might establish a bank, and potential bank sites; establishing trading rules with appropriate local water quality management authorities; and obtaining approval of the proposed trading program from the U.S. EPA.The second major issue addressed in the paper is means by which an offset bank might be created. For this purpose, a brief survey is offered of existing water quality trading projects in the U.S.. Buyers of offset credits are virtually always point-source polluters (POTWs or industries). Point and non-point projects have been used as "banks" -- as a source for offset banking credits. Attention in this paper is focused on non-point sources that might serve as banks for pilot offset banking projects in Georgia. Both low- and high-technology alternatives that might be used for such projects are discussed.Notwithstanding incentive-related limitations on the number of point source polluters that might constitute the "demand" for offset credits discussed in section II, the authors have identified one entity (Fulton County) that may represent significant demand for credits, and they expect to identify others. Moreover, the authors argue that continued growth in Georgia, particularly in the Atlanta and Coastal areas of the State, will give rise to sufficient numbers of point source entities seeking new discharge permits to warrant interest in offset banking as a means of meeting increasingly stringent discharge restrictions at minimum cost. If or when enforcement of TMDLs gains strength in the State, needs for systems like offset banking will increase accordingly. These considerations, and the associated benefits to Georgians that might attend the establishment of offset banking programs in the State, serve as the rationale for the author's continued interest in exploring means by which pilot offset banking projects can be established in Georgia. Working Paper # 2003-00
Serrated trailing edges for improving lift and drag characteristics of lifting surfaces
An improvement in the lift and drag characteristics of a lifting surface is achieved by attaching a serrated panel to the trailing edge of the lifting surface. The serrations may have a saw-tooth configuration, with a 60 degree included angle between adjacent serrations. The serrations may vary in shape and size over the span-wise length of the lifting surface, and may be positioned at fixed or adjustable deflections relative to the chord of the lifting surface
Estimation of Costs of Phosphorus Removal In Wastewater Treatment Facilities: Adaptation of Existing Facilities
As part of a wider enquiry into the feasibility of offset banking schemes as a means to implement pollutant trading within Georgia watersheds, this is the second of two reports addressing the issue of estimating costs for upgrades in the performance of phosphorus removal in point-source wastewater treatment facilities. Earlier, preliminary results are presented in Jiang et al (2004) (Working Paper # 2004-010 of the Georgia Water Planning and Policy Center). The present study is much more detailed and employs an advanced software package (WEST®, Hemmis nv, Kortrijk, Belgium) for simulating a variety of treatment plant designs operating under typical Georgia conditions. Specifically, upgrades in performance, in a single step, from a plant working at an effluent limit of less than 2.0 mg/l phosphorus to one working with limits variously ranging between less than 1.0 mg/l to less than 0.05 mg/l phosphorus are simulated and the resulting costs of the upgrade estimated.Five capacities of plant are considered, from 1 MGD to 100 MGD. Three strategic, alternative designs for the facility are considered: the basic activated sludge (AS) process with chemical addition, the Anoxic/Oxic (A/O) arrangement of the AS process, and the Anaerobic/Aerobic/Oxic (A/A/O) arrangement of the AS process. Upgrades in performance are consistent with the logical alternatives for adapting these options. Cost comparisons are made primarily on the basis of the incremental cost of the upgrade, i.e., from the base-case, reference plant to that performing at the higher level, as expressed through the incremental Total Annual Economic Cost (TAEC; in /kg).For the most stringent upgrade, for example, to a plant generating an effluent with less than 0.05 mg/l phosphorus, these marginal costs -- the cost of the additional phosphorus removed as a result of the upgrade -- amount to something of the order of 150-425 $/kg, with the upper bound being associated with the smallest plant configuration (1 MGD). Working Paper Number 2005-001
A Ternary Lattice Boltzmann Model for Amphiphilic Fluids
A lattice Boltzmann model for amphiphilic fluid dynamics is presented. It is
a ternary model, in that it conserves mass separately for each chemical species
present (water, oil, amphiphile), and it maintains an orientational degree of
freedom for the amphiphilic species. Moreover, it models fluid interactions at
the microscopic level by introducing self-consistent forces between the
particles, rather than by positing a Landau free energy functional. This
combination of characteristics fills an important need in the hierarchy of
models currently available for amphiphilic fluid dynamics, enabling efficient
computer simulation and furnishing new theoretical insight. Several
computational results obtained from this model are presented and compared to
existing lattice-gas model results. In particular, it is noted that lamellar
structures, which are precluded by the Peierls instability in two-dimensional
systems with kinetic fluctuations, are not observed in lattice-gas models, but
are easily found in the corresponding lattice Boltzmann models. This points out
a striking difference in the phenomenology accessible to each type of model.Comment: 12 pages, 6 figures included with graphic
Star Formation in Tadpole Galaxies
Tadpole Galaxies look like a star forming head with a tail structure to the
side. They are also named cometaries. In a series of recent works we have
discovered a number of issues that lead us to consider them extremely
interesting targets. First, from images, they are disks with a lopsided
starburst. This result is firmly established with long slit spectroscopy in a
nearby representative sample. They rotate with the head following the rotation
pattern but displaced from the rotation center. Moreover, in a search for
extremely metal poor (XMP) galaxies, we identified tadpoles as the dominant
shapes in the sample- nearly 80% of the local XMP galaxies have a tadpole
morphology. In addition, the spatially resolved analysis of the metallicity
shows the remarkable result that there is a metallicity drop right at the
position of the head. This is contrary to what intuition would say and
difficult to explain if star formation has happened from gas processed in the
disk. The result could however be understood if the star formation is driven by
pristine gas falling into the galaxy disk. If confirmed, we could be unveiling,
for the first time, cool flows in action in our nearby world. The tadpole class
is relatively frequent at high redshift - 10% of resolvable galaxies in the
Hubble UDF but less than 1% in the local Universe. They are systems that could
track cool flows and test models of galaxy formation.Comment: arXiv admin note: text overlap with arXiv:1302.435
Formation of massive clouds and dwarf galaxies during tidal encounters
Gerola et al. (1983) propose that isolated dwarf galaxies can form during galaxy interactions. As evidence of this process, Mirabel et al. (1991) find 10(exp 9) solar mass clouds and star formation complexes at the outer ends of the tidal arms in the Antennae and Superantennae galaxies. We describe observations of HI clouds with mass greater than 10(exp 8) solar mass in the interacting galaxy pair IC 2163/NGC 2207. This pair is important because we believe it represents an early stage in the formation of giant clouds during an encounter. We use a gravitational instability model to explain why the observed clouds are so massive and discuss a two-dimensional N-body simulation of an encounter that produces giant clouds
A Robust Numerical Method for Integration of Point-Vortex Trajectories in Two Dimensions
The venerable 2D point-vortex model plays an important role as a simplified
version of many disparate physical systems, including superfluids,
Bose-Einstein condensates, certain plasma configurations, and inviscid
turbulence. This system is also a veritable mathematical playground, touching
upon many different disciplines from topology to dynamic systems theory.
Point-vortex dynamics are described by a relatively simple system of nonlinear
ODEs which can easily be integrated numerically using an appropriate adaptive
time stepping method. As the separation between a pair of vortices relative to
all other inter-vortex length scales decreases, however, the computational time
required diverges. Accuracy is usually the most discouraging casualty when
trying to account for such vortex motion, though the varying energy of this
ostensibly Hamiltonian system is a potentially more serious problem. We solve
these problems by a series of coordinate transformations: We first transform to
action-angle coordinates, which, to lowest order, treat the close pair as a
single vortex amongst all others with an internal degree of freedom. We next,
and most importantly, apply Lie transform perturbation theory to remove the
higher-order correction terms in succession. The overall transformation
drastically increases the numerical efficiency and ensures that the total
energy remains constant to high accuracy.Comment: 21 pages, 4 figure
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