Digital Literacy Circulation: Adolescents and Flows of Knowledge about New Media

The aim of this paper is to discuss the output of an empirical research on digital skills in order to develop a typology of skills circulation among young digital users. Relying on research on digital literacy in media studies and on users in STS, in this article we start criticizing the concepts of \u201cdigital divide\u201d, \u201cdigital inequalities\u201d and \u201cdigital competencies\u201d. Then, we present the principal results of a research study involving 50 adolescents in Italy about how they acquired their competences in the use of digital media. This gave us the opportunity to focus on the digital skills of young people and the development of their abilities in using digital media. The research outlines the patterns of circulation in digital competences among young people in relation to family, school and peer group, defining four kinds of \u201cflows\u201d: parental flow (involving fathers and mothers), peer flow (connected to friends and people of the same age), educational flow (referring to formal education) and technological flow (involving technological devices, such as computers, laptops, smartphones, tablets, etc.). The aim is to understand the interactions between digital skills and the social, institutional and technological conditions that influence the youth\u2019s digital literacy for the everyday use of digital media

Predictive Methods and Analysis of Time Dependent Tritium Flow Rates and Inventories in Fusion Systems

In nuclear fusion reactors, tritium dynamics plays a dominant role. An unprecedented amount of tritium is consumed in Deuterium-Tritium (D-T) nuclear fusion reactors, ~0.5 kg per day for 3 GW fusion power. However, tritium is radioactive, has short half-life (~12.33 years), and is present in nature in negligible concentration. Because of tritium scarcity, future fusion power reactors must be self-sufficient, i.e. the reactor must have a closed fuel cycle where tritium is produced in greater amounts than it is consumed. Furthermore, nuclear fusion reactors must accumulate and provide tritium start-up inventory for the next generation of fusion power plants, since natural reserves of tritium are very limited. Moreover, because of its radioactive nature, tritium presents a serious hazard to the personnel and has implications to safety and nuclear licensing.Accurate predictive models of the nuclear fusion fuel cycle are required to effectively design the fuel cycle components, understand tritium dynamics in the fusion fuel cycle, and determine the technology and physics requirements to attain tritium self-sufficiency. Moreover, accurate predictions of tritium inventories and flow rates within fusion components, and estimations of tritium releases to the environment are necessary for nuclear licensing. In this dissertation, two numerical models are developed to perform tritium transport assessment within fusion systems. First, a high fidelity numerical model is developed to simulate time-dependent tritium transport within the reactor outer fuel cycle (OFC). Detailed (high resolution) component-level models, where constitutive transport equations are implemented in COMSOL Multiphysics and solved for various fusion sub-systems, are integrated into system-level with the use of MATLAB/Simulink S-Functions to reproduce typical OFC tritium streams. The model is applied to the KOrean Helium Cooled Ceramic Reflector Test Blanket System (KO-HCCR TBS) which will be tested in the International Thermonuclear Experimental Reactor (ITER). However, the developed model offers some flexibility and can be applied to other Test Blanket Module (TBM) designs. Second, the overall fusion fuel cycle is modeled analytically by a system of time-dependent zero-dimensional ordinary differential equations with the tritium mean residence time method. This technique yields results useful for understanding the overall fuel cycle dynamics and the importance of certain components and parameters. The analysis of tritium inventories and flow rates is extended to determine the physics and technology requirements to attain tritium self-sufficiency. In particular, the state-of-the-art plasma physics and technology parameters (e.g. tritium burn fraction, fueling efficiency, processing times, etc.) and up-to-date fuel cycle design are considered in the analysis. The tritium self-sufficiency assessment and tritium start-up inventory evaluation are performed to investigate: (i) the effect of the reactor operating scenario and availability factor, e.g. to account for random failures and ordinary maintenance, (ii) the scenarios for commercialization, e.g. risk associated with tritium reserve inventory reduction, (iii) the penetration of fusion energy into power market, e.g. effect of the doubling time, and (iv) the effect of reactor power on tritium start-up inventory, e.g. for plasma-based test facilities, DEMOnstration reactors (DEMO), and power reactors. The results highlight the physics and technology R&D requirements to attain fuel self-sufficiency in fusion reactors

Comparative cytotoxicity evaluation of eight root canal sealers

The aim of the present study is to evaluate and compare the cytotoxic effects of eight root canal sealers (BioRoot RCS, TotalFill BC Sealer, MTA Fillapex, Sealapex, AH Plus, EasySeal, Pulp Canal Sealer, N2) on immortalized human gingival fibroblasts over a period of 24, 48 and 72 hours. Immortalized human gingival fibroblast-1 HGF-1 (ATCC CRL-2014) were incubated. Root canal sealers were then placed into sterile, cylindrical Teflon moulds. The extraction was made eluting the sealers in cell culture medium. Cells (1 × 104) were seeded in each well of a 96-well plate and incubated for 24 h at 37°C. Cultures were then exposed to 100 ?L of the extracts medium. The percentage of viable cells in each well was calculated relative to control cells set to 100%. BioRoot RCS and TotalFill BC Sealer extracted for 24h showed no cytotoxic effect, while it was mild by using 48 and 72 h extracts. No cytotoxic effect was measured by using AH Plus medium eluted for 24 h, while it was moderate after 48 h and severe after 72 h. Pulp Canal Sealer, Sealapex and N2 showed moderately cytotoxic activity for all the extraction times. EasySeal and MTA Fillapex remained severely or borderline mildly cytotoxic for all the extraction times. In the present study only BioRoot RCS, TotalFill BC Sealer and AH Plus showed no cytotoxic effects at least in the first 24h. All the other sealers revealed moderately or severely cytotoxic activity during all the extraction times

Entwicklung und Charakterisierung von Sialon-Keramiken und Sialon-SiC-Verbunden für den Einsatz in tribologisch hochbeanspruchten Gleitsystemen

Tribologisch hoch beanspruchte Gleitsysteme wie Hochdruckpumpen für die Benzindirekteinspritzung besitzen ein Belastungskollektiv, das Werkstoffe mit niedrigen Reibungszahlen und geringem Verschleiß bei gleichzeitig hoher mechanischer Festigkeit erfordert. Im Rahmen dieser Arbeit wurden Sialon-Keramiken für derartige Anwendungen entwickelt und charakterisiert. Diese zeigten hervorragende mechanische und tribologische Eigenschaften und somit ein hohes Potential für diesen Einsatzbereich

Energy Technologies for Food Utilization for Displaced People: from identification to evaluation

By end-2014, the number of forcibly displaced people in the World was 59.5 million, the highest after the II World War. UNHCR (2015) reports that they are 19.5 million refugees, 38.2 internally displaced persons (IDPs) and 1.8 asylum-seekers, and they have been progressively increased in number for the last 4 years, with an estimation of 13.9 newly displaced in 2014. Such people have several needs, especially in terms of food security. Humanitarian actors usually try to address them focusing on food availability and access, while food utilization is often neglected (Haver K., Harmer A., Taylor G., 2013). The utilization of food, including the access to drinking water, is one of the four pillars of food security, and affects food properties in terms of nutritional intake, especially micronutrients, and healthiness (European Commission, 2009). Appropriate technologies for cooking, food preservation, and water purification are required, but all of them entail the access to fuel or other energy sources. Indeed, access to energy for displaced people is very important from different perspectives, but it is often problematic, and entails five key challenges: “protection, relations between hosts and displaced people, environmental problems, household energy-related natural resource restrictions and livelihood-related challenges” (Lyytinen 2009, pag. 1). The importance of energy for development was pointed out by the Sustainable Energy for All (SE4All) Initiative, while Safe Access to Fuel and Energy (SAFE) focused the attention on crisis-affected populations, in particular refugees and IDPs (SAFE, 2015). Indeed, if people living in camps, and similarly in informal settlements, are provided with energy services, they may access to a wide range of opportunities to change their condition, and conduct a more productive and active life (Bellanca, 2014). Unfortunately, several gaps are still present in humanitarian response for providing displaced people with an adequate access to energy, and studies are few, mainly related to stoves and generally without an independent impact assessment (Gunning, 2014). Very few displaced people have access to modern forms of energy: generally their practices are unsustainable, with average household costs of at least 200 USD per year (family of five) and disproportionate CO2 emission compared to quantity and quality of energy finally utilized (Lahn & Grafham, 2015). Therefore, the gap in giving the right importance to energy access – in particular in linking relief, rehabilitation and development – is clear