Extensions of Von Neumann's theory of economic growth

In this thesis some simplified assumptions present in the von Neumann expanding economy are examined and replaced by more appropriate ones. First we explain more clearly the von Neumann original model and the Kemeny Morgenstern and Thompson's extension. We clarify the meaning of the open constrained economy which Morgenstern and Thompson derive from the von Neumann economy as a linear programming problem. Then we examine the exact meaning and relevance, in the ambit of the von Neumann's model, of different definitions of closed economy, in connection with the treatment of labour. We study critically all the ways of introducing consumption into the model. After we deal with the models which explicitly introduced externalities and processes which produce both goods and bads. Some of the previous generalizations have not been completely free from criticism; however some shortcomings can be solved introducing externalities as different commodities, distinguished on the basis of their users. These public intermediate commodities influence directly the use and the intensity of one or more productive processes. They are also one of the premises and foundations of the public sector normative and positive theory of De Viti De Marco. In our models we follow his line of reasoning and confine ourselves to the original (or KMT) model. We show how the rate of growth of the von Neumann's economy, where the prices of public commodities (bads) are determined by the equilibrium solution and paid through taxation, is greater than the one which would be determined by the private market equilibrium where public commodities (bads) are free. It is also possible to have no private market equilibrium, even if it always exists a constrained one which is a mixed economy equilibrium

Validation in agent-based models: an investigation on the CATS model

In this paper we deal with some validation experiments on the complex adaptive trivial system (CATS) model proposed in Gallegati et al. [Gallegati, M., Giulioni, G., Palestrini, A., Delli Gatti, D., 2003a. Financial fragility, patterns of firms’ entry and exit and aggregate dynamics. Journal of Economic Behavior and Organization 51, 79–97; Gallegati, M., Delli Gatti, D., Di Guilmi, C., Gaffeo, E., Giulioni, G., Palestrini, A., 2005. A new approach to business fluctuations: heterogeneous interacting agents, scaling laws and financial fragility. Journal of Economic Behavior and Organization 56, 489–512]. In particular starting from a sample of Italian firms included in the AIDA database, we perform several ex post validation experiments over the simulation period 1996–2001. In the experiments, the model parameters have been estimated using actual data and the initial set up consists of a sample of agents in 1996. The CATS model is then simulated over the period 1996–2001. Using alternative validation techniques, the simulations’ results are ex post validated respect to the actual data

Removal of Hg from Real Polluted Sediments Using Enhanced-EK Decontamination: Verification of Experimental Methods and Batch-Test Preliminary Results

The aim of the research is to apply a biosurfactant-enhanced-EK technology to marine sediment contaminated by high level of Hg. In this work, data from batch-tests using different novel biosurfactant agents were reported. In addition, a dedicated EK bench-scale apparatus was designed and carried out. Technical test was also performed to evaluate the optimal operating features of the EK bench-scale apparatus, assessing the influence of applied voltage and treatment time on the current intensity and electroosmotic flow. Batch experiments were conducted using two sugar esters as biosurfactants and EDTA salt at different concentrations. Results showed that the maximum extraction efficiency was observed for the biosurfactant Olimpicon GC (15%), for which the Hg extraction was shown to be 3.6-fold higher than for 0.2 M EDTA. From technical tests, the observed reduction of current intensity and electroosmotic flow with time highlights the necessity of using conditioning agents during the treatment. Data demonstrates also the good working features of the experimental apparatus. Preliminary results show that EK treatment jointly with biosurfactants such as sugar esters could be a better choice for the remediation of Hg-polluted sediments. The results obtained are of scientific and practical interest and can be used for further researches

Development of a performance threshold approach for identifying the management options for stabilisation/solidification of lead polluted soils

Two soils spiked with lead at different rates were stabilised/solidified using Portland cement and fy ash at different soil:binder ratios, and tested for their setting time, unconfined compressive strength, leachability and durability. A performance threshold approach was used in order to identify optimal management options for the products of the S/S treatment. Results show that soil texture, percentage of binders and lead concentration play an important part in the treatment, significantly influencing the performance of the resulting products in terms of curing, compressive strength and durability. Pb soil concentrations higher than 15000 mg kg-1 were found to heavily reduce the applicability of the treatment requiring the maximum amount of binder in order to satisfy the performance criteria. Te performance of sandy soils was shown to be limited by setting time and UCS features due to the retardation of the hydration reactions and also by its leaching behaviour, whereas for silt-clayey soils the critical parameter is the mechanical resistance

Remediation of Hg-contaminated marine sediments by simultaneous application of enhancing agents and microwave heating (MWH)

The aim of this work was to investigate Hg removal ability of a novel microwave heating (MWH) treatment for marine sediment remediation enhanced by the application of several agents, biodegradable complexing agent (methylglycinediacetic acid, MGDA), surfactant (Tween® 80), and citric acid. Main results revealed that MWH allowed a very rapid heating (∼450 °C in 7 min) of the irradiated medium. However, without the addition of enhancing agents, a maximum Hg removal of ∼72% can be achieved. The application of MGDA led to a higher contaminant removal of ∼87% (residual concentration = 5.4 mg kg−1). For the treatment including the simultaneous addition of both chelating agent and surfactant, their synergetic action and stripping processes resulted in a very high Hg removal of ∼99% for an irradiation time of 7 min, corresponding to a residual concentration of 0.56 mg kg−1, which is lower than the Italian regulatory limit of 1 mg kg−1. The use of citric acid resulted in a shortening of the removal kinetics, which allowed the successful application of a shorter remediation time of 5 min. The observed strong passive ability of sediments to convert a microwave irradiation energy into a rapid and large temperature increase undoubtedly represents a key factor in the whole remediation process, making the studied treatment an excellent choice. Kinetic data are suitable for a preliminarily assessment of the effectiveness of clean-up activities, and as basis for future scaling-up studies on MWH of Hg-contaminated sediment

Competition under non-linear pricing: the optimal entry tax with a public firm

University of Edinburgh Discussion Paper in Economic

La questione della valutazione del benessere di generazioni differenti

ECOFIN Discussion Papers

“Il possibile ruolo del TFR nel futuro sistema pensionistico"

ECOFIN, Discussion Paper