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The recent miniaturization of components in manufacturing has increased the production of lightweight and sophisticated systems in many different industrial fields. Micro-electro discharge machining (micro-EDM) is a technology widely used for these applications. Although it is a well-known technology, there are still a few research works which investigate the economic implications of this process. This paper reports a model to estimate micro-EDM costs, including both fixed and variable costs. The aim of this model is to estimate the overall manufacturing costs, taking into account production and manufacturing process, tool and workpiece information. A process-based cost calculation method is used for this purpose. The model was applied to two case studies, based on the execution of micro holes, performed on stainless steel and tungsten carbide plates using different electrode materials. The capability of the model was finally demonstrated. [ABSTRACT FROM AUTHOR]

Radon is considered one of the short- and immediate-term earthquake precursors by International Association of Seismology and Physics of the Earth's Interior. For this reason, the accurate and reliable measurement of its specific activity in soil gas is mandatory. Since its presence is influenced by many environmental factors, in order to eliminate this influence on the radon activity measurement a multi-parametric and multi-site analysis is necessary. Following this approach, a continuous radon monitoring was carried out in two sites of the Phlegrean Fields caldera (Campania, Italy) using the RaMonA system, which also allows for the measurement of temperature, relative humidity and pressure. In particular, the dependence of measured radon specific activity on the meteorological conditions was studied using the multiple linear regression method. The analysis was implemented also by testing data averages on different timescales. In this paper, the results of a preliminary analysis performed on data collected throughout 2012 are presented; the outcomes obtained allow to emphasize site-specific behavior and to discriminate apparent radon 'anomalies' of climatic origin from those tied to the phenomena occurring in the earth's crust. The method employed showed its usefulness by removing the effects of meteorological conditions and thus to better identify the possible radon anomalies caused by seismo-volcanic activity. The peculiarities of the different sites and some correlations with earthquakes are discussed. [ABSTRACT FROM AUTHOR]

The present work deals with the execution of through micro-holes on stainless steel plates using a micro-EDM (Electrical discharge machining) machine. The investigation focuses on the influence of different electrodes' materials and power discharge on both the process performance and the dimensional characteristics of the holes. The experimental campaign was carried out by varying peak current and voltage in order to achieve both high and low power discharge conditions. Tubular electrodes made of three different materials (tungsten carbide, brass and copper) were used. The indexes taken into account were Material removal rate (MRR), Tool wear ratio (TWR), Diametral overcut (DOC) and Taper rate (TR). Brass and copper electrodes always resulted to be the best solution in terms of drilling speed even though the wear of these electrode types is remarkable higher than the tungsten one. On the opposite, tungsten carbide electrodes resulted to be the best solution when high dimensional and geometrical precision is required. Concerning the finishing of the hole inner surface, the best results were achieved using tungsten carbide electrode. [ABSTRACT FROM AUTHOR]

The aim of the paper is to give information about radon concentration in air and in water of 16 thermal spas of the Isle Ischia to assess the corresponding mean effective dose for workers. Measurements of air radon concentration were carried out by means of Electret Passive Environmental Radon Monitor (E-PERM) devices in long-term configuration, while radon activity concentration in water was measured using the same detectors in short-term configuration. In each plant, several kinds of rooms of different uses (office, muddy room, massage room, relax room, aerosol, mud pit and medical treatment room) were selected. Results show a great variability among the measurements relative to the different kinds of rooms of the spas. In some cases, the dose received by workers was higher than 3 mSv/y, which is the effective dose limit for occupational exposure imposed by Italian legislation. [ABSTRACT FROM AUTHOR]

In this study, the indoor radon activity concentrations have been measured in the Neapolitan catacombs using LR115 detectors. The detectors were exposed for two quarters, one in the warm season and the other in the cold. This has allowed one to evaluate the seasonal variations of concentrations, while the diurnal variations were evaluated performing continuous measurements by a Radim 5 monitor. The authors found that radon concentrations were lower in winter than in summer. Based on their values, taking into consideration the working hours in the catacombs and the equilibrium factor of 0.4, the effective dose to workers was estimated. [ABSTRACT FROM PUBLISHER]

Plants can be exposed to ionising radiation not only in Space but also on Earth, due to specific technological applications or after nuclear disasters. The response of plants to ionising radiation depends on radiation quality/quantity and/or plant characteristics. In this paper, we analyse some growth traits, leaf anatomy, and ecophysiological features of plants of Solanum lycopersicum L. "Microtom" grown from seeds irradiated with increasing doses of X-rays (0.3,10,20,50, and 100 Gy). Both juvenile and compound leaves from plants developed from irradiated and control seeds were analysed through light and epifluorescence microscopy. Digital image analysis allowed quantifying anatomical parameters to detect the occurrence of signs of structural damage. Fluorescence parameters and total photosynthetic pigment content were analysed to evaluate the functioning of the photosynthetic machinery. Radiation did not affect percentage and rate of seed germination. Plants from irradiated seeds accomplished the crop cycle and showed a more compact habitus. Dose-depended tendencies of variations occurred in phenolic content, while other leaf anatomical parameters did not show distinct trends after irradiation. The sporadic perturbations of leaf structure, observed during the vegetative phase, after high levels of radiation were not so severe as to induce any significant alterations in photosynthetic efficiency. [ABSTRACT FROM AUTHOR]