In mainstream economic theory money functions as an instrument for the circulation of commodities or for keeping a stock of liquid wealth. In neither case is it considered fundamental to the production of goods or the distribution of income. Augusto Graziani challenges traditional theories of monetary production, arguing that a modern economy based on credit cannot be understood without a focus on the administration of credit flows. He argues that market asset configuration depends not upon consumer preferences and available technologies but on how money and credit are managed. A strong exponent of the circulation theory of monetary production, Graziani presents an original and perhaps controversial argument that will stimulate debate on the topic.
Nowadays, wind energy plays a key role as a sustainable source of energy and wind turbines are a relevant source of power for many countries world-wide. In such a context, this paper investigates the technical and economic feasibility of small wind turbines for five of the main European Union countries (France, Germany, Italy, Spain and The Netherlands). Ten commercial turbines with rated power from 2.5 kW to 200 kW are evaluated considering their installation and operative conditions. Several parameters most affecting wind turbine performances are evaluated and the estimation of the annual cash flows during the expected plant life-time are determined as a function of both the installation location (wind speed probability distribution, national incentive scheme and tax level) and the wind turbine characteristics (rated power curve, maintenance, installation and shipping costs). The obtained data are presented and discussed through a parametric analysis based on the Net Present Value capital budget approach, showing the conditions making these systems profitable or non-profitable and explaining the relative motivations. Moreover, the analysis outcomes are further investigated highlighting the dependence of the turbine profitability from the considered parameters, including a comparative analysis among the five analyzed European countries
Cataclastic rocks and fault gouge present highly variable properties, from those of soil-like materials to those of competent rock mass. In most cases, the entire rock mass, or internal major shear zones, can be represented as a block-in-matrix rock (bimrock), i.e., rock fragments of different shape and size, embedded in a finer matrix. In this paper, a tectonized metamorphic rock mass at the site of a planned gravity dam is investigated. The dam foundation is crossed by numerous major discontinuities, often grouped to form wider shear zones and characterized by high persistency, waviness, and abundant cataclastic filling. Systematic measurements of local orientation and filling thickness along the discontinuity traces made a detailed morphological analysis possible. The most frequent type of filling is a lightly cemented matrix-supported gouge. Undisturbed sampling of filling materials was successful only in some special cases. Laboratory tests, as well as in-situ mechanical tests, were therefore difficult and not exhaustive. Micromechanical distinct-element method (DEM) modeling was instrumental in obtaining a more comprehensive framework of deformation and failure mechanisms of cataclastic materials. The mechanical properties of the particulate model were first analyzed by numerical simulation of biaxial and direct shear tests. The relationship between the overall constitutive parameters and micromechanical properties, such as interparticle friction, contact stiffness, cement bond strength, volumetric block proportion, and block shape, was determined. The complex interplay between the geometric features of a major discontinuity (joint-wall roughness and waviness) and the properties of the infilling bimrock was then investigated, and finally, the overall strength of the infilled discontinuity was analyzed. (C) 2012 American Society of Civil Engineer
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