Joseph J. Harrington

Detection of Planetary Emission from the Exoplanet Tres-2 Using Spitzer/IRAC

We present here the results of our observations of TrES-2 using the Infrared Array Camera on Spitzer. We monitored this transiting system during two secondary eclipses, when the planetary emission is blocked by the star. The resulting decrease in flux is 0.127% ± 0.021%, 0.230% ± 0.024%, 0.199% ± 0.054%, and 0.359% ± 0.060% at 3.6 μm, 4.5 μm, 5.8 μm, and 8.0 μm, respectively. We show that three of these flux contrasts are well fit by a blackbody spectrum with T_(eff) = 1500 K, as well as by a more detailed model spectrum of a planetary atmosphere. The observed planet-to-star flux ratios in all four IRAC channels can be explained by models with and without a thermal inversion in the atmosphere of TrES-2, although with different atmospheric chemistry. Based on the assumption of thermochemical equilibrium, the chemical composition of the inversion model seems more plausible, making it a more favorable scenario. TrES-2 also falls in the category of highly irradiated planets which have been theoretically predicted to exhibit thermal inversions. However, more observations at infrared and visible wavelengths would be needed to confirm a thermal inversion in this system. Furthermore, we find that the times of the secondary eclipses are consistent with previously published times of transit and the expectation from a circular orbit. This implies that TrES-2 most likely has a circular orbit, and thus does not obtain additional thermal energy from tidal dissipation of a non-zero orbital eccentricity, a proposed explanation for the large radius of this planet.

MATHEMATICAL MODELS FOR DEVELOPING REGIONAL SOLID WASTE MANAGEMENT POLICIES

Abstract Various mathematical programming models are applied to evaluate operational (static one-period) and dynamic investment. (multiperiod) policies of regional solid waste management (SWM). Special attention is paid to the use of mixed integer programming (MIP) models for dynamic investment policies. The common objective of minimizing the present value of overall investment and/or management costs is extended to deal explicitly with land-use policies by evaluating the sequencing of landfilling operations. The question of abandonment or upgrading of facilities is introduced into the mathematical framework because of its importance in the light of more restrictive standards. The decision as to which process should be installed at what location and at what time, as well as the decision which landfill should be operated and when, is identified in the MIP model. Considering the limitations of the data base and the model formalism, the question of the usefulness of relying on one optimal solution from a mod...

An Applied General Equilibrium (AGE) analysis of a policy designed to reduce the household consumption of wood in the Sudan

Abstract The Sudan, along with all Sahelian countries, faces urgent environmental problems caused, in part, by the clear-cutting of scrub for firewood. In this paper, we analyze the economic consequences of a policy often proposed to reduce the consumption of firewood. Specifically, we simulate the policy of introducing more efficient wood burning stoves into households by using an Applied General Equilibrium (AGE) model. The results indicate that the anticipated reduction in the economy-wide demand for wood, based on the increase in the technical efficiency of the stoves, is not fully realized.

A partial equilibrium analysis of the impact of introducing more-efficient wood-burning stoves into households in the Sahelian region

Two models of the village firewood-gathering economy are developed: one where the firewood is treated by households as a common-property resource and one where it is treated as a private asset. Under both models, rebound of consumption occurs as a result of distributing more-efficient wood-burning stoves into households. It follows that policies premised on the assumption that the use of scarce resources can be curtailed simply by raising the energy efficiency of appliances used in the household are flawed. The same policies, however, when judged according to their contribution to the utility of the household appear to be better.

A Model of Sustainable Extraction of Nontimber Forest Products in Subsistence Societies

The shrinking forest in many parts of the world is a problem often blamed on the patterns of ownership and harvesting by the resource owners. We develop a model which demonstrates that holding a resource in common where there is competition among individuals leads to inefficient harvesting of the resource but cannot lead to the destruction of forests. The same model is used to demonstrate that climatic conditions, low wage rates, and increases in the number of people entitled to harvest the resource are more-likely candidates for variables explaining the destruction of the forest. Examples taken from the Sudan and from China provide evidence that communities alter their pattern of ownership and migration so that they do not exhaust the resource. The main conclusion of the paper is that the behavior of the owners of the resource is not the underlying cause of the destruction of the forest.

Strategies for the Optimal Control of Dust Emissions from Unpaved Roads

Travel on unpaved public roads is the single largest anthropogenic source of emissions of airborne particles in the U.S. The average impact of this source on average annual mean total suspended particulate (TSP) concentrations varies from 0.05 μg/m3 (Alaska) to 11 μg/m3 (Pennsylvania). When compared by contributions to the variance in state to state TSP levels, their impact is as great as the impact of emissions from all conventional sources. Common emission control methods include paving, oiling, speed reduction, watering, and application of calcium chloride. Total annual emissions are, in most cases, most economically reduced by either speed control or paving, with expected average control costs of less than

Generating alternative designs for interjurisdictional natural resource development schemes in the Greater Ganges River basin

0.50/lb of emissions reductions. For most roads with average daily traffic flows above 100 vehicles per day, paving is shown to control emissions at average costs of less than

Analysis of Variability in Loadings On a Municipal Refuse Incinerator

0.05/lb. In some situations, the costs of paving are more than offset by reductions in maintenance costs. Thus it would ap...

Program scheduling of interrelated programs in a university faculty when there might be strategic behavior

Planning for the development of regional water resources is often complicated by severe disputes. For example, in the Greater Ganges River basin, there are disagreements between India and Bangladesh over sharing the low river flows during the dry season and over controlling the potentially destructive large river flows during the monsoon. This paper illustrates an approach for providing the two riparian nations with distinct water resources plans to help solve their regional water conflicts. More specifically, a linear programming (LP) model representing a multipurpose river basin system is presented. The concept of near optimality is employed to generate a variety of solutions, in contrast to searching only for a global optimum. These solutions are grouped into similar project designs by applying a cluster analysis, which is a multivariate technique. Several project designs are graphically displayed, and their implications for national and international agreements are discussed. The range of regional alternatives available to India and Bangladesh could aid in their negotiations.

HYDRAULIC DESIGN OPTIMIZATION OF ELECTRODIALYSIS FOR DEMINERALIZING BRACKISH WATERS

The trend toward increased use of central refuse incinerators is inevitably contributing to urban air pollution. Eventually sampling ports, emission sensing and recording equipment will be required; and more detailed data will be available. But, tradilionally, discharges have been estimated by means of emission factors for nominal design loadings. Such estimates may be unreliable, especially under highly variable processing rates. Preliminary evidence suggests lhat actual emission factors are higher when the incinerator is charged at greater rates, and vice versa. Observations at the Boston municipal incinerator indicate considerable day-to-day variability in refuse loading. No measurements of emissions are made, but daily input loading records for several years are available. This study focuses upon the variability in daily loadings. Several functions relating emission factors to charging rates are assumed in order to estimate variability in discharges to the atmosphere. Four years of daily records were ...