Economical comparison of CHP systems for industrial user with large steam demand

In this paper cogeneration benefits applied to a user with a high steam demand are analyzed. The methodology for the feasibility study and the economical analysis of the investment is presented under the Italian legislative framework. The methodology is applied to an actual case and a detailed description and discussion of all data input is provided. Especially this last key point will be faced using starting data usually available in these kind of studies (i.e., not very detailed for thermal consumption). Finally a comparison of different CHP technologies and a sensitivity analysis is done

High-performance magnetic shielding solution for extremely low frequency (ELF) sources

Some particular aspects related to open shields with high performance are presented. The magnetic flux density targets related to the protection of sensitive devices are quite low, <0.2 µT. The problem to reach high magnetic field attenuation is more complicated by the fact that open shields have to be adopted instead of closed solutions. After some general considerations about open shields two practical examples are presented and discussed

Magnetic field in an apartment located above 10/0.4 kV substation: Levels and mitigation techniques

The paper presents a real case of non-ionising radiation testing in an apartment located directly above a 10/0.4 kV substation in Serbia. In order to check the compliance with national regulations on protection of population from non-ionising radiation, it was necessary to perform measurements of magnetic flux density in the apartment. After the first measurements were performed, the distribution company implemented a mitigation technique by placing a passive conductive shield inside the substation in order to decrease magnetic field levels in the apartment. Measurements performed after the mitigation technique had been implemented have shown that the applied shield had an impact on magnetic field reduction to a certain extent. However, since the obtained shielding factor was not very high, the authors analysed another possible shielding solution which would provide higher shielding factor and consequently lower magnetic field levels in the apartment. Both shielding solutions and the results they provide are presented and analysed

Mitigation Solutions for the Magnetic Field Produced by MFDC Spot Welding Guns

Among the different welding technologies, portable welding guns are one of the most critical devices in relation to human exposure to electromagnetic fields. This paper focuses on medium frequency (MF) direct current guns proposing two actions aimed to the mitigation of the magnetic field generated during the welding process. The first action consists in the adoption of a passive shield for the on-board MF transformer. The analysis points out that the transformer alone produces a magnetic field that can exceed the prescribed limits. Therefore, a suitable mitigation system is identified. The second action aims to mitigate the predominant magnetic field that is generated by the electrodes of the welding gun. The analysis of the field waveforms shows that the rise time of the welding current pulse is the main parameter affecting the exposure index. The effect of the increase of the rise time is investigated through experimental and numerical analyses. The results prove that a small increase of the rise time causes a significant reduction of the exposure level. It is noteworthy that the two mitigation actions can be adopted on both existing and newly developed welding guns as they do not require any structural modification of the welding device

A proposal for performance evaluation of low frequency shielding efficiency

The present work aims to propose a methodology for evaluating the performance of low-frequency magnetic shields used for the shielding of complex sources such as MV/LV substations. Today there is no standard procedure for testing shields based on the use of a single-coil for generating artificial MF (MF: Magnetic Field) as is the case for high-frequency anechoic chambers. In the case of shielding for industrial frequency sources, these are generally open shields with sources of various types: 3D transformers, switch-gear, and power lines. These kinds of sources and shields are better checked if the artificial MF has all three components in space. The work proposes a methodology based on the use of a tri-axial source, capable of generating a rotating magnetic field. The supports of the coils are made using a 3D printing process. The paper presents the design steps, the analytical evaluation of the performance of the source and as an application a test of a magnetic shielding plate was presented

Identification of material properties and optimal design of magnetically shielded rooms

In this paper, we propose an optimal design procedure for magnetically shielded rooms. Focusing on multi-layer ferromagnetic structures, where inner layers operate at very low magnetic field, we propose an identification method of the magnetic material characteristic in the Rayleigh region. A numerical model to simulate the shielding efficiency of a multi-layer ferromagnetic structure is presented and experimentally tested on different geometries and layer configurations. The fixed point iterative method is adopted to handle the nonlinearity of the magnetic material. In conclusion, the optimization of the design parameters of a MSR is discussed, using the Vector Immune System algorithm to minimize the magnetic field inside the room and the cost of the structure. The results highlight that a linear magnetic characteristic for the material is sufficient to identify the suitable geometry of the shield, but the nonlinear model in the Rayleigh region is of fundamental importance to determine a realistic shielding factor

OpenCoesione and Monithon - a Transparency Effort

Context OpenCoesione is the first portal about the fulfilment of investments and projects planned by the Italian central government and by the Italian Regions using the 2007­2013 European Cohesion funds. Together with Monithon, it is a “transparency tool” whose aim is to foster participation of the citizens and efficiency of the public sector bodies in order to improve the implementation of development policies. By now it is one of the best Open Data portal in Italy quality­wise. Objective Our goal is to show the utility of these portals, how this open information is supposed to help the civil society and how data quality might affect reuse. Method We engage in the empirical observation on how data are exposed and used, discussing specific examples, and applying some data quality metrics. Results We present some evidences on how open data can positively affect the public sector bodies and the spending of funds. Conclusions Under­spending of EU Cohesion funds is a serious problem in Italy. OpenCoesione and Monithon can contribute solving this inefficiency, e.g., by presenting data in such a (standardised) way to enable their elaboration by third partie

Efficient parametrization of complex molecule-surface force fields

We present an efficient scheme for parametrizing complex molecule-surface force fields from ab initio data. The cost of producing a sufficient fitting library is mitigated using a 2D periodic embedded slab model made possible by the quantum mechanics/molecular mechanics scheme in CP2K. These results were then used in conjunction with genetic algorithm (GA) methods to optimize the large parameter sets needed to describe such systems. The derived potentials are able to well reproduce adsorption geometries and adsorption energies calculated using density functional theory. Finally, we discuss the challenges in creating a sufficient fitting library, determining whether or not the GA optimization has completed, and the transferability of such force fields to similar molecules. © 2015 Wiley Periodicals, Inc