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Microwave characterization and shielding properties of biochar based polymers and cements
No full textRecently, in composites production the attention has been focused on the study of ecofriendly materials derived from recycling. In geographical areas where biomass and other biogenic wastes are abundant, it is advantageous to find new applications for these production scarps. Biochar is a solid material derived by pyrolysis of biomass. It is characterized by high carbon contain, and for this reason, it can be thinking as substitute of more expensive carbon filler in polymers
Prediction of product morphology of lyophilized drugs in the case of Vacuum Induced Surface freezing
No full textEgli's Mülkiye: Ankara's Modern Heritage and Its Transformation
No full textModern architecture, especially in the non-European territories, has been utilized to represent a breaking point from the past. This pattern has repeated also in Turkey to create a secular modern nation (Turkey Republic) out of a centuries-old Islamic dynasty (the Ottoman Empire). Foreign architects have been invited by the young Republic not only to design the cities and buildings but also to teach in academia. Austrian-Swiss architect Ernst Egli (1893-1974) has been one of the prominent names of European architects/planners whose works constitute Ankara's modern heritage. His 1936 project for the School of the Political Sciences represents the modern face of Turkish Republic. This research analyzes the place that this campus building holds within the modern architectural heritage of the Republican era, and it assesses the place of this heritage in the memory of people
Milling and quite-fast sintering as key production steps to obtain fully dense PZTN-CF particulate composites
No full textIn the near future (within ten years) magnetoelectric multiferroics could be implemented into the emerging technologies such as wireless power, internet of things, machine-to-machine communication services, mesh network, etc. Remarkable efforts have been done to develop laminated bi-layer and multilayer multiferroic composites as bulk or thin films. These structures lead to remarkable magneto-electric coupling coefficients of a few Volts / cm∙Oe because the ferroic layer is a "full dielectric" which can be completely poled in the conventional way. On the other hand in the particulate ceramic composites the requirement for "full dielectric" is no longer applicable, since the ferroic phases are fully separated within the composite. The strengths of particulate ceramic composites are low cost, simple production technology, higher strain mediated magneto-electric coupling (since electric order phase/magnetic phase interface density can be higher) and easy control of electrical and magnetic properties if the ferroelectric phase (generally a perovskite) and the ferromagnetic one (a ferrite with spinel structure) are mixed in a favourable proportion under the percolation threshold of the ferromagnetic phase. A great research effort is in progress to improve the fabrication of PZT-CoFe2O4 (PZT- CF) composites in order to avoid the unwanted reactions, which occur during densification of PZT-CF materials at 1100-1200 °C, and to achieve the electric saturation during the poling. Up to date, by setting a quite-fast sintering, full densification and prevention of unwanted reactions were achieved for the PZT:CF 74:26 composites,1 but achieving electric saturation is still a challenge. Further important results were: the understanding that the main cause of reactions is the PbO loss;1 the proposal of an equation to calculate the PbO loss through XRD analysis, considering the amount of ZrO2 and variation of perovskite's tetragonality;1 and the ability to design the ceramic process (milling of the CF powers in particularly) to control the CF grain size distribution, which can be mono- or bi-modal, and overgrowth.1,2 References 1. P. Galizia, C.E. Ciomaga, L. Mitoseriu and C. Galassi, "PZT-cobalt ferrite particulate composites: Densification and lead loss controlled by quite-fast sintering", J. Eur. Ceram. Soc., 37, pp. 161-168, 2016. 2. P. Galizia, C. Baldisserri, C. Capiani and C. Galassi, "Multiple parallel twinning overgrowth in nanostructured dense cobalt ferrite", Mater. Design, 109, pp. 19-26, 2016
Spectrum Fees and Market Performance: a Quantitative Analysis
No full textThis paper aims at providing evidence on the impact of spectrum fees and spectrum availability on mobile operators' industry revenues by using an original dataset of firms operating in 24 Countries in the period 2005-2014. The analysis quantitatively identifies the relationship between mobile market revenue and their determinants, among which spectrum availability and license fees are included. The analysis provides evidence that spectrum availability and fees are not significantly correlated with mobile industry revenues suggesting that market expectations to extract additional revenues from the mobile service following new spectrum auctions are likely not to be respected
Network Traffic Measurements, Applications to Internet Services and Security
No full textThe Internet has become along the years a pervasive network interconnecting billions of users and is now playing the role of collector for a multitude of tasks, ranging from professional activities to personal interactions. From a technical standpoint, novel architectures, e.g., cloud-based services and content delivery networks, innovative devices, e.g., smartphones and connected wearables, and security threats, e.g., DDoS attacks, are posing new challenges in understanding network dynamics. In such complex scenario, network measurements play a central role to guide traffic management, improve network design, and evaluate application requirements. In addition, increasing importance is devoted to the quality of experience provided to final users, which requires thorough investigations on both the transport network and the design of Internet services. In this thesis, we stress the importance of users' centrality by focusing on the traffic they exchange with the network. To do so, we design methodologies complementing passive and active measurements, as well as post-processing techniques belonging to the machine learning and statistics domains. Traffic exchanged by Internet users can be classified in three macro-groups: (i) Outbound, produced by users' devices and pushed to the network; (ii) unsolicited, part of malicious attacks threatening users' security; and (iii) inbound, directed to users' devices and retrieved from remote servers. For each of the above categories, we address specific research topics consisting in the benchmarking of personal cloud storage services, the automatic identification of Internet threats, and the assessment of quality of experience in the Web domain, respectively. Results comprise several contributions in the scope of each research topic. In short, they shed light on (i) the interplay among design choices of cloud storage services, which severely impact the performance provided to end users; (ii) the feasibility of designing a general purpose classifier to detect malicious attacks, without chasing threat specificities; and (iii) the relevance of appropriate means to evaluate the perceived quality of Web pages delivery, strengthening the need of users' feedbacks for a factual assessment
Trust in SDN/NFV environments
No full textSDN/NFV techniques are growing in popularity. They are powerful and flexible but less secure because they exploit specific software modules running at the nodes of a highly distributed infrastructure. Due to errors or attacks, the node can be easily compromised to alter its behaviour. In order to tackle this issue, we exploit remote attestation, a well-known technique to assess the software integrity of a node. Unfortunately, it only works well with physical platforms but not so well in virtualized environments. This paper presents our insights to adopt remote attestation in SDN/NFV environments. We show the possible approaches to attest the software integrity inside virtualised instances in practice and show their respective performance results and limitations. Further we present a SDN verifier to attest the OpenFlow rules loaded in the NFV nodes and the improvements to push the performance of remote attestation to its limit. In the end, we talk about the recent efforts in standardising remote attestation in NFV
Identification of accident sequences for the DEMO plant
No full textSafety studies are performed in the frame of the conceptual design studies for the European Demonstration Fusion Power Plant (DEMO) to assess the safety and environmental impact of design options. An exhaustive set of reference accident sequences are defined in order to evaluate plant response in the most challenging events and compliance with safety requirements.The Functional Failure Mode and Effect Analysis (FFMEA) has been chosen as analytical tool, as it is a suitable methodology to define possible accident initiators when insufficient design detail is available to allow for more specific evaluation at component level. The main process, safety and protection functions related to the DEMO plant are defined through a functional breakdown structure (FBS). Then, an exhaustive set of high level accident initiators is defined referring to loss of functions, rather than to specific failures of systems and components, overcoming the lack of detailed design information. Nonetheless reference to systems or main components is always highlighted, as much as possible, in order to point out causes and safety consequences. Through the FFMEA a complete list of postulated initiating events (PIEs) is selected as the most representative events in terms of challenging conditions for the plant safety. All the four blanket concepts of the European DEMO reactor have been analysed