7,518 research outputs found
Facing up to inequality and exclusion to end poverty and hunger in Latin America:
Poverty reduction, Hunger, Inequality, Extreme poverty, Poverty reduction programs, Growth and targeted poverty reduction,
Numerical simulation of radionuclides migration in the far field of a geological repository
Safety conditions associated with geological repositories must be guaranteed also in the case of
radionuclides migrating from the near field to the far field of a geological repository and to the external
environment. For this reason the migration process of radionuclides and the factors affecting the process
patterns have a crucial importance. In the present article, in order to simulate the migration process of
radionuclides in the far-field of a geological repository, the groundwater simulation code PMWIN
(Processing Modflow) is used, following a methodology applied by the same authors in a previous work.
The present case study refers to a non-uniform groundwater flow field and shows the influence of two
important parameters, the distribution coefficient and the hydraulic gradient. The results are compared
with the ones previously obtained for the uniform flow case and the different scenarios are discussed
Exergy analysis of a PWR nuclear steam supply system – Part I, general theoretical model
The paper provides an alternative, novel methodology to perform the exergetic analysis of a Pressurized Nuclear Reactor (PWR) based on the strictest definition of fission temperature to get to a careful evaluation of Exergy Destruction and exergetic Efficiency of the component.
Up today, the exegetic analyses of Nuclear Power Plants (NPP) have been based on the assumption that Fission Exergy and Fission Energy are almost the same having assumed Carnot Factor almost equal to 1 as Tfiss >>T0. This assumption is based on some simplified hypotheses concerning fission temperature as applied in the definition of the Fission Exergy itself, whose value, to the best knowledge of the authors, was never modeled.
On the contrary, in the first part of the paper, the authors present the results of an ongoing research, just aimed at evaluating the Exergy efficiency of the heat exchange in a PWR reactor, whose first results were already presented in [1], based on the most detailed modeling of Tfiss. The modeling, referring to a steady-state operational mode of the Reactor, takes into account all heat transfer phenomena between nuclear fuel UO2, its Zircaloy clad, cooling water, vessel material and the external environment.
In the second part of the paper, the Exergy analysis is extended to all main Reactor Cooling System components (Vertical recirculating type Steam Generator, primary coolant pump and piping) with the aim to compare the Exergy Destructions and exergetic Efficiencies of the RPV with those of the other components of the Nuclear Steam Supply System, NSSS.
In the Part II of the same paper,, "Exergy Analysis of a PWR Nuclear Steam Supply System - II part: a case study ", a test case is exemplified with the aim to compare the results obtained applying the methodology in question with those obtained applying the most established methodology adopted by other authors
Exergy analysis of a PWR nuclear steam supply system - II part: a case study
The paper shows the results of the exergetic analysis of the Nuclear Steam Supply System (NSSS) of the MARS Pressurized Light Water Reactor using the theoretical methodology described in the authors’ previous works [1] and [2]. The analysis firstly aims at a novel assessment of the irreversibilities occurred in the nuclear reactor vessel to compare the results, in terms of Exergy Destruction and exergetic Efficiency, with those obtained adopting one of the most employed methodology as reference.
The comparison showed that a detailed exergetic analysis, mainly aimed to strictly assess the fission temperature, can lead to a higher estimate of the PWR exergetic Efficiency values
On Productivity Measurement and Interpretation: Some Insights on Italy in the European Context. LEQS Paper No. 142/2019 March 2019
Over the period 1995–2016, the Italian performance in terms of productivity was poor in
historical terms and in comparison with its main international partners. This issue goes beyond
Italy, with declining productivity growth observed, from the second half of the nineties, in
several other advanced economies. Possible explanations for the slowdown include factors
such as lower capital investment by firms, decreased competition, excessive regulation, and
capital misallocation. The diffuse slowing rates of measured productivity growth has also
raised questions on whether GDP and output current compilation methods are adequate (i.e.
the mis-measurement hypothesis). The “ICT revolution” has created new ways of exchanging
and providing goods and services as result of increased connectivity. These developments
challenge the way economic activity is traditionally measured. There are also measurement
problems associated with estimating output and input volumes especially related to the quality
of price indexes for some products and services. These problems have an impact on
productivity estimates and might impair international comparability. In this paper, we intend to
investigate what the core problems in productivity measurement and interpretation are in the
European context, with a specific focus on Italy
Multiple filtering devices for the estimation of cyclical DSGE models
We propose a method to estimate time invariant cyclical DSGE models using the information provided by a variety of filters. We treat data filtered with alternative procedures as contaminated proxies of the relevant model-based quantities and estimate structural and non-structural parameters jointly using a signal extraction approach. We employ simulated data to illustrate the properties of the procedure and compare our conclusions with those obtained when just one filter is used. We revisit the role of money in the transmission of monetary business cycles.DSGE models, Filters, Structural estimation, Business cycles
Did Tax Policies mitigate US Business Cycles?
I study whether US Tax Policies affected economic volatility during the post World War II period. I employ a Real Business Cycle model with distorting taxation on household income and tax rules, and assume that taxes respond to the cyclical conditions of the economy. I estimate the deep parameters of the model using Bayesian techniques. My findings are; (a) fiscal policies display a strong countercyclical behavior, (b) help to reduce the cyclical and raw volatility of GDP, consumption, investment when the government can issue debt, and (c) unexpected changes in tax policies do not affect the volatility of the macroeconomic variables.Fiscal Policy and Business Cycles, Bayesian Methods.
- …