The size and shape of equilibrium capillary surfaces

The classical theory of capillary is concerned largely with size and shape estimates in symmetric asymptotic configurations. Recent developments leading to global results for all symmetric cases, and to qualitative information on asymptotic properties are discussed. Additional stability criteria are described. Asymmetric situations leading to behavior that differs strikingly from the symmetric case are discussed. When gravity vanishes, capillary surfaces in the accustomed sense may not appear. The question of characterizing those tubes in which surfaces can be found has partially been settled. Progress toward determining the effects of contact angle hysteresis in cases of particular interest is reported

The Anatomy of Market Power in Electricity Markets with Hydropower as Dominating Technology

The problem of optimal management of a water reservoir by a hydropower producer is necessarily a dynamic one since water can be transferred between periods. A hydropower producer being a monopolist cannot reduce output in the classical way without spilling water. He will follow a strategy of setting marginal revenues equal between time periods and thus shift water from relatively inelastic periods to relatively elastic ones. If the monopolist has thermal capacity the strategy is the same, but the utilization of thermal capacity is reduced. If the monopolist has control over external trade import is reduced and export increased compared with the social solution. Technical constraints of limited reservoir and interconnector capacity and a competitive fringe may reduce markedly the consequences of exercising market power.Hydropower, thermal power, market power, flexibility-corrected price, competitive fringe.

An extreme ultraviolet photoemission study Final report

Photoelectric emission properties of iron, copper, nickel, aluminum, and molybdenu

Categorical variables in DEA.

If a DEA model has a mix of categorical and continuous variables a standard LP formulation can still be used by entering all combinations of categorical and continuous variables as different types of inputs and/or outputs. Most units will then not have positive levels of all variables. The implications for selection of peers are investigated. Peers can have the same or fewer types of inputs than the unit under investigation, but either fewer or more types of outputs. There is a basic asymmetry between number of positive inputs and outputs of the peer units due to more of inputs reducing efficiency while more of outputs improving efficiency. The special cases of imposing a hierarchical structure on the categorical variables dealt with in the literature can easily be incorporated.Categorical variable; DEA; efficiency; linear programming; peer

The performance of auction houses selling Picasso Prints.

It has been observed that similar prints can obtain quite different prices at different auctions within the same auction period. Previous works applying hedonic price technique to determine the formation of auction prices of objects of art have found no conclusive result about the impact of auction houses on final prices. In these studies the object of art has been the unit, and influence of auction houses is analysed by testing whether auction house impact on price is significant or not within a framework of central tendencies. In order to focus on auction houses as a unit we have applied a benchmarking technique, DEA, developed for efficiency studies. Performance indexes are defined and calculated giving an insight into auction house differences difficult to obtain using hedonic price approach.Performance; auction house; Picasso prints; hedonic price; benchmarking; best practice; DEA

The Compensation mechanism in the rains model: the Norwegian targets for acidification.

The RAINS model is used to calculate cost minimising abatement policies subject to European-wide spatial restrictions on pollution. The principle for choosing environmental targets for the 1994 Oslo Protocol was closing a gap between benchmark- and critical loads for each grid with a uniform percentage. During the negotiations for the 1999 Gothenburg Protocol accumulated ecosystems exceedances was adapted as basis for gap closure, and overshooting of the constraints allowed as an option, provided compensation could be found within the same country. A theoretical discussion of this compensation mechanism is provided. A simulation study, using the full RAINS model, of the impact of different levels of targets for troublesome Norwegian grids is presented, and results in the form of changes in accumulated acidity excesses and costs for the participating countries are reported.Acid rain; RAINS; critical loads; gap closure; accumulated exceedances; compensation mechanism

Calculating the scale elasticity in DEA models.

In economics scale properties of a production function is charcterised by the value of the scale elasticity. In the field of efficiency studies this is also a valid approach for the frontier production function. It has no good meaning to talk about scale properties of inefficient observations. In the DEA literature a qualitative characterisation is most common. The contribution of the paper is to apply the concept of scale elasticity from multi output production theory in economics to the piecewise linear frontier production function, and to develop formulas for calculating values of the scale elasticity for radial projections of inefficient observations. Illustrations also on real data are provided, showing the differences between scale elasticity values for the input- and output oriented projections and the range of values for efficient observations.Scale elasticity; DEA, production theory; Farrell efficiency measures

Properties of a Non-Competitive Electricity Market Dominated by Hydroelectric Power

An important conclusion from the literature on hydropower is that if there are no other constraints than the available water reservoirs for a year, and operating costs are ignored, the competitive (and socially optimal) outcome is characterized by the (present value) price being constant through the year. A second important conclusion is that the outcome under monopoly generally will differ from this, provided that the demand functions differ across different days (or other sub-periods) of the year. We show that even if the demand function is the same all days of the year, the monopoly outcome will generally differ from the competitive outcome. The difference is caused by the profit function of a price-setting producer of hydropower being non-concave. This non-concavity can be caused by short-run capacity limits either on exports and imports of electricity, or on the supply of alternative electricity sources.Electricity prices, Hydropower