``The choice between emission taxes and output taxes under imperfect monitoring": a comment

We consider a special case of Schmutzler's and Goulder''s (1997) analysis of output taxes vs emission taxes as environmental policy instruments. We identify new necessary conditions for the existence of an optimum. We also show that, in this case, it is always optimal to have a mixed tax with positive enforcement effort.

Assessing the Distributional Impacts of Transferable Pollution Permits: The Case of Phosphorus Pollution Management at a River Basin Scale

Although the initial allocation of pollution permits is neutral in terms of efficiency, it does have a significant impact on distributive equity. In this paper, we examine the two main categories of permit allocation rules, the distributive and the reductive, for controlling phosphorus pollution in a small catchment in South West England. Based on the premise that the regulatory choice compromises efficiency and equity, the main result of this paper is that an allocation of permits in proportion to the intensity of environmental preferences is a “win-win†choice. The reason is that it simultaneously achieves two goals. First, it is efficient (or cost-effective) since a permit system achieves a prespecified target at a minimum abatement cost, while second, it is the only allocation rule which reduces the income inequality of the baseline scenario.pollution permits, phosphorus, nutrient management, export coefficient model, water quality, distributive justice, income inequality, Atkinson Index, Environmental Economics and Policy,

Price induced water irrigation: Unraveling conflicts and synergies between European agricultural and water policies

The 2003 CAP reform considerably affects cropping patterns in European agriculture. At the same time the imperatives of the forthcoming Water Framework Directive (WFD) is expected to modify irrigation decisions especially in Southern Europe where irrigated agriculture utilizes about 70-80% of total water. This paper examines the combined effect of CAP reform and the application of likely volumetric water pricing on water demand by taking into account three drivers of change, namely extensive margin changes, intensive margin changes and irrigation technology shift. For low rates of water prices, CAP reform contradicts the WFD objectives since it leads to cropping patterns that consume more water resources. On the contrary, as water prices increase, decoupling and water pricing display a synergistic effect on water conservation. Finally, decoupling substantially increases the efficiency of water pricing in terms of water conservation. As a result, the post CAP reform regime clearly dominates the prior CAP reform regime when an index of value for money water conservation is examined.irrigation, bio-economic modeling, mathematical programming, policy analysis, price endogenous model, water demand, CAP reform, WFD

The Impact of River Flow Restrictions on Instruments to Control noPoint Nitrate Pollution

An economic analysis of policies to control nonpoint source nitrate pollution in the presence of minimum river flow restrictions was undertaken. A non-linear bio-physical economic optimisation model of an intensively cultivated Scottish agricultural catchment was constructed. The presence of minimum river flow controls in the catchment was found to reduce nitrogen pollution. However, by themselves, river flow controls were found not to be a cost effective means to reduce diffuse pollution. River flow controls did not, for the most part, alter relative instrument ranking.

Analyticity and causality of the three-parameter rheological models

In this paper the basic frequency response and time response functions of the three-parameter Poynting-Thomson solid and Jeffreys fluid are revisited. The two rheological models find application in several areas of rheology, structural mechanics and geophysics. The relation between the analyticity of a frequency response function and the causality of the corresponding time-response function is established by identifying all singularities at ω=0 after applying a partial fraction expansion to the frequency response functions. The strong singularity at ω=0 in the imaginary part of a frequency response function in association with the causality requirement, imposes the addition of a Dirac delta function in the real part in order to make the frequency response function well defined in the complex plane. This external intervention, which was first discovered by P.A.M. Dirac, has not received the attention it deserves in the literature of viscoelasticity and rheology. The addition of the Dirac delta function makes possible the application of time domain techniques that do not suffer from violating the premise of causality

The engineering merit of the “Effective Period” of bilinear isolation systems

This paper examines whether the “effective period” of bilinear isolation systems, as defined invariably in most current design codes, expresses in reality the period of vibration that appears in the horizontal axis of the design response spectrum. Starting with the free vibration response, the study proceeds with a comprehensive parametric analysis of the forced vibration response of a wide collection of bilinear isolation systems subjected to pulse and seismic excitations. The study employs Fourier and Wavelet analysis together with a powerful time domain identification method for linear systems known as the Prediction Error Method. When the response history of the bilinear system exhibits a coherent oscillatory trace with a narrow frequency band as in the case of free vibration or forced vibration response from most pulselike excitations, the paper shows that the “effective period” of the bilinear isolation system is a dependable estimate of its vibration period; nevertheless, the period associated with the second slope of the bilinear system is an even better approximation regardless the value of the dimensionless strength of the system. As the frequency content of the excitation widens and the intensity of the acceleration response history fluctuates more randomly, the paper reveals that the computed vibration period of the systems exhibits appreciably scattering from the computed mean value. This suggests that for several earthquake excitations the mild nonlinearities of the bilinear isolation system dominate the response and the expectation of the design codes to identify a “linear” vibration period has a marginal engineering merit

Transverse versus longitudinal eigenperiods of multispan seismically isolated bridges

This paper is motivated from the wider need in system identification studies to identify and interpret the eigenvalues of seismically isolated bridges from field measurements. The paper examines the transverse eigenvalues of multispan bridges which are isolated in both transverse and longitudinal directions at all supports including all center piers and end-abutments. The paper shows that regardless of the value of the longitudinal isolation period of the deck, the length of the bridge and the number of spans, the first transverse (isolation) period is always longer than the longitudinal isolation period of the deck. This result cannot be captured with the limiting idealization of a beam on continuously distributed springs (beam on Winkler foundation) which yields the opposite result–that the first transverse period is always shorter than the longitudinal isolation period. This fundamental difference between the response of a flexural beam supported on distinct, equally spaced springs and that of a beam supported on continuously distributed springs has not received the attention it deserves in the literature of structural mechanics-dynamics. Finally, the paper shows that the first normalized transverse eigenperiod of any finite-span isolated deck follows a single master curve and the solutions from all configurations are self-similar and are not dependent on the longitudinal isolation period or on whether the deck is isolated on elastomeric or spherical sliding bearings

Size versus slenderness: Two competing parameters in the seismic stability of free-standing rocking columns

When a free-standing column with a given base becomes taller and taller, there is a competition between the increase in its size (more stable) and the increase in its slenderness (less stable). This paper investigates how these two competing phenomena affect the stability of tall, slender, free-standing columns when subjected to horizontal and vertical ground shaking. The main conclusion of the paper is that the outcome of this competition is sensitive to local details of the ground shaking and the dominant frequency of a possible coherent, distinguishable pulse. The often observed increase in stability due to increase in height (despite the increase in slenderness) may be further enhanced due to a sudden transition from the lower mode of overturning with impact to the higher mode of overturning without impact. The paper proceeds by offering a simple mathematical explanation why the vertical ground acceleration has a marginal effect on the stability of a slender, free-standing column; and concludes that the level of ground shaking that is needed to overturn a tall free-standing column of any size and any slenderness is a decreasing function of the length scale, apTp^2, of the dominant coherent acceleration pulse normalized to the base-width of the column

Time and frequency domain identification of seismically isolated structures: advantages and limitations

This paper investigates the effectiveness of widely used identification methods to identify the response of seismically isolated structures supported on bearings with bilinear behavior. The paper shows that while both time domain and frequency domain methods predict with high accuracy the modal characteristics of structures isolated by linear isolation system, their performance degrades appreciably when the isolation system exhibits bilinear behavior even when its strength assumes moderate values (say 5% of the weight). The paper also shows that the natural period of isolated structure that results from bilinear isolation systems can be satisfactorily predicted with wavelet analysis

Estimating the “Effective Period” of Bilinear Systems with Linearization Methods, Wavelet and Time-Domain Analysis: From Inelastic Displacements to Modal Identification

This paper revisits and compares estimations of the effective period of bilinear systems as they result from various published equivalent linearization methods and signal processing techniques ranging from wavelet analysis to time domain identification. This work has been mainly motivated from modal identification studies which attempt to extract vibration periods and damping coefficients of structures that may undergo inelastic deformations. Accordingly, this study concentrates on the response of bilinear systems that exhibit low to moderate ductility values (bilinear isolation systems are excluded) and concludes that depending on the estimation method used, the values of the “effective period” are widely scattered and they lie anywhere between the period-values that correspond to the first and the second slope of the bilinear system. More specifically, the paper shows that the “effective period” estimated from the need to match the spectral displacement of the equivalent linear system with the peak deformation of the nonlinear system may depart appreciably from the time needed for the nonlinear system to complete one cycle of vibration. Given this wide scattering the paper shows that for this low to moderate ductility values (say ) the concept of the “effective period” has limited technical value and shall be used with caution and only within the limitations of the specific application