A multiple-scale model for compressible turbulent flows

A multiple-scale model for compressible turbulent flows is proposed. It is assumed that turbulent eddy shocklets are formed primarily by the 'collisions' of large energetic eddies. The extra straining of the large eddy, due to their interactions with shocklets, enhances the energy cascade to smaller eddies. Model transport equations are developed for the turbulent kinetic energies and the energy transfer rates of the different scale. The turbulent eddy viscosity is determined by the total turbulent kinetic energy and the rate of energy transfer from the large scale to the small scale, which is different from the energy dissipation rate. The model coefficients in the modeled turbulent transport equations depend on the ratio of the turbulent kinetic energy of the large scale to that of the small scale, which renders the model more adaptive to the characteristics of individual flow. The model is tested against compressible free shear layers. The results agree satisfactorily with measurements

On the Basic Equations for the Second-order Modeling of Compressible Turbulence

Equations for the mean and the turbulence quantities of compressible turbulent flows are derived in this report. Both the conventional Reynolds average and the mass-weighted Favre average were employed to decompose the flow variable into mean and turbulent quantities. These equations are to be used later in developing second-order Reynolds stress models for high-speed compressible flows. A few recent advances in modeling some of the terms in the equation due to compressibility effects are also summarized

Searching out of Trading Noise: A Study of Intraday Transactions Cost

We attempt to identify in this paper the role of trading noise as a transactions cost to market participant in the sense of Stoll (2000), especially in the presence of trading concentration. Applying the measures of Hu (2006) and Kang and Yeo (2008), we analyze the noise proportion in intraday stock returns and its interaction with investor herding and search cost. Although this noise is high on individual orders and low on institutional orders, its behavior at market open is entirely different from the rest of the day. Noises for small cap stocks, unlike volatilities, are lower than those for large cap stocks. We also found that noise relates positively to trading volume, but inversely to holdings and turnover ratio of institutional investors. Responses from institutional and individuals are quite the opposite. The noise proportion generated by individual order rises with institutional turnover and search cost encountered, while that of institutional order behaves just oppositely. At market open, behaviors of noise from institutional and individual orders just switch mutually, and then switch back afterwards. Also, noise from high-cap stocks is actually more responsive than that from low-cap ones across investors. So trading noise is a specific transactions cost, prominent to only certain investors, at certain time and for certain stocks in the market, rather than a general market friction as argued in Stoll (2000). This transactions cost is inversely related to search costs encountered in trading, which depends on investor, trading hour of day and market capitalization of stocks.Noise, transaction cost, herding, search model, order book

Jobs Versus the Environment: An Industry-level Perspective

The possibility that workers could be adversely affected by environmental policies imposed on heavily regulated industries has led to claims of a "jobs versus the environment" trade-off by both business and labor leaders. The present research examines this claim at the industry level for four heavily polluting industries: pulp and paper mills, plastic manufacturers, petroleum refiners, and iron and steel mills. By focusing on labor effects across an entire industry, we construct a measure relevant to the concerns of key stakeholders, such as labor unions and trade groups. We decompose the link between environmental regulation and employment into three distinct components: factor shifts to more or less labor intensity, changes in total expenditures, and changes in the quantity of output demanded. We use detailed plant-level data to estimate the key parameters describing factor shifts and changes in total expenditures. We then use aggregate time-series data on industry supply shocks and output responses to estimate the demand effect. We find that increased environmental spending generally does not cause a significant change in industry-level employment. Our average across all four industries is a net gain of 1.5 jobs per $1 million in additional environmental spending, with a standard error of 2.2 jobs—an insignificant effect. In the plastics and petroleum sectors, however, there are small but significantly positive effects: 6.9 and 2.2 jobs, respectively, per$1 million in additional expenditures. These effects can be linked to favorable factor shifts—environmental spending is more labor intensive than ordinary production—and relatively inelastic estimated demand.

The Cost of Environmental Protection

Expenditures for environmental protection in the U.S. are estimated to exceed $150 billion annually or about 2$1.50 to $12. This paper explores the relationship between reported expenditures and economic cost in the manufacturing sector in the context of a large plant-level data set at the four-digit SIC level. We use a cost function modeling approach which treats both environmental and non-environmental production activities as distinct, unrelated cost minimization problems for each plant. We then explore the possibility that these activities are, in fact, related by including reported regulatory expenditures in the cost function for non-environmental output. Under the null hypothesis that reported regulatory expenditures accurately measure the cost of regulation, the coefficient on this term should be zero. In ten of eleven industries studied, including all of the heavily regulated industries, this null hypothesis is accepted using our preferred fixed-effects model. Our best estimate, based on an expenditure weighted average of the four most heavily regulated industries, indicates that an incremental dollar of reported environmental expenditure reduces non-environmental production costs by eighteen cents with a standard error of forty-two cents. This is equivalent to saying that total costs rise by eighty-two cents for every dollar increase in reported environmental expenditures. Using an alternative pooled model we find uniformly higher estimates. Although consistent with previous results, we believe these higher estimates are biased by omitted variables characterizing differences among plants. Summarizing, our results enable us to reject claims that environmental spending imposes large hidden costs on manufacturing plants. In fact, our best estimate indicates a modest though statistically insignificant overstatement of regulatory costs.

Evaluating Voluntary Climate Programs in the United States

Despite serving as the principal basis of U.S. climate policy over the past two decades, corporate voluntary environmental programs have been subject to quite limited evaluation. The self-selection of participants—an essential element of such initiatives—poses particular challenges to researchers because the decision to participate may not be random and, in fact, may be correlated with the outcomes. The present study is designed to overcome these problems by gauging the environmental effectiveness of two early voluntary climate change programs with established track records, the U.S. Environmental Protection Agency’s Climate Wise program and the U.S. Department of Energy’s Voluntary Reporting of Greenhouse Gases Program, or 1605(b). Both programs provide quite flexible criteria for firms to participate. Particular attention is paid to the participation decision and how various assumptions affect estimates of program outcomes using propensity score matching methods applied to plant-level Census data. Overall, we find quite modest effects: the reductions in fuel and electricity expenditures from Climate Wise and 1605(b) are no more than 10 percent and probably less than 5 percent. Virtually no evidence suggests a statistically significant effect of either Climate Wise or 1605(b) on fuel costs. Some evidence indicates that participation in Climate Wise led to a slight (3–5 percent) increase in electricity costs that vanished after two years. Stronger evidence suggests that participation in 1605(b) led to a slight (4–8 percent) decrease in electricity costs that persisted for at least three years.voluntary, regulation, energy, climate change

Technology Adoption and Aggregate Energy Efficiency

Improved technology is often cited as a means to alter the otherwise difficult trade-off between the economic burden of regulation and environmental damage. Focusing on energy-saving technologies that mitigate the threat of climate change, we find that both energy prices and financial health influence technology adoption among a sample of industrial plants in four heavily polluting sectors. Based on a model linking technology adoption to growth in aggregate efficiency, we estimate that a doubling of energy prices, after raising the growth rate to 2.1%, would require slightly more than 50 years to generate a 50% improvement in aggregate efficiency relative to the baseline forecast.energy efficiency, endogenous technological change, technology adoption

Workshop Report: Pollution Abatement Costs and Expenditures (PACE) Survey Design for 2000 and Beyond

Accurate estimates of pollution abatement costs are crucial elements of any rational effort to set or evaluate environmental policies. One of the primary sources of this information in the United States has been the Bureau of the Census (BOC) Pollution Abatement Costs and Expenditures (PACE) survey, which collected annual establishment-level data on abatement costs for most years between 1972 and 1994. After a five-year lapse, the PACE survey was restarted in 2000, collecting 1999 data. Yet as firms have turned to more comprehensive abatement strategies involving process and design changes, pollution prevention, and recycling, the PACE survey has faced a number of problems that limit its ability to accurately measure abatement costs. At the same time, both national and international interest in understanding the true costs of environmental protection has grown, along with the complexity of the research and policy issues currently under discussion. There is now widespread interest in redesigning the PACE survey to improve its usefulness to policymakers as well as to researchers. In March 2000, Resources for the Future (RFF) convened an expert workshop to consider a wide range of issues relevant to future PACE surveys. This report describes the workshop and derives a number of conclusions based on discussions at the workshop.