Atomistic fracture: QFM vs. MD

In this work we discuss the paradigmatic case of brittle fracture in defective elastic-plastic cubic silicon carbide, by a combination of Quantized Fracture Mechanics and Molecular Dynamics atomistic simulations. Different defect sizes and shapes, or crack-inclusion interactions are considered. Our results show that Quantized Fracture Mechanics is able to effectively incorporate the main lattice-related features, while Molecular Dynamics atomistic simulations do provide the most basic level of understanding of mechanical behaviour of brittle materials.     

Sustainability assessment of hydrogen production by steam reforming

A specific methodology was applied to investigate the expected impact on sustainability of processes for hydrogen production by steam reforming of natural gas. Reference process schemes based on the current industrial state-of-the-art and on innovative steam reforming technologies were defined and assessed. The methodology allowed the calculation of a sustainability “fingerprint” of the reference schemes, based on sustainability key performance indicators. The results obtained evidenced the potential advantages of innovative processes, based on integrated conversion and internal membrane separation reactors. However, the valorization of the by-product streams is an essential requirement to reduce the impact on sustainability of these processes. Besides the improvement of the reaction section, the optimization of the overall separation efficiency and of energy requirement emerged as the key elements that control the overall sustainability performance of these processes.     

A stochastic interspecific competition model to predict the behaviour of <Emphasis Type="Italic">Listeria monocytogenes</Emphasis> in the fermentation process of a traditional Sicilian salami

The present article discusses the use of modified Lotka–Volterra equations in order to stochastically simulate the behaviour of Listeria monocytogenes and lactic acid bacteria (LAB) during the fermentation period (168 h) of a typical Sicilian salami. For this purpose, the differential equation system is set considering temperature (T), pH, water activity (aw) as stochastic variables. Each of them is governed by dynamics that involve a deterministic linear decrease as a function of the time t and an “additive noise” term which instantaneously mimics the fluctuations of T, pH and aw. The choice of a suitable parameter accounting for the interaction of LAB on L. monocytogenes as well as the introduction of appropriate noise levels allows to match the observed data, both for the mean growth curves and for the probability distribution of L. monocytogenes concentration at 168 h.     

Architecture and testbed implementation of vertical handovers based on SIP session border controllers

This paper describes a Session Initiation Protocol (SIP) based solution for mobility management that provides seamless mobile multimedia services in a heterogeneous scenario where different radio access technologies are used (802.11/ WiFi, Bluetooth, 2.5G/3G networks). The solution relies on the so called “Session Border Controllers” which are now widely used in many commercial SIP telephony solutions, mainly to deal with NAT traversal. Session Border Controller functionality has been extended to support seamless mobility for multimedia applications. A prototype of the proposed solution focused on VoIP services has been implemented in a test bed which is able to perform seamless handovers (and NAT traversal) using the 802.11, Bluetooth and 3G (UMTS) access networks. Measurements results are reported which analyze the performance of the solution in a real world environment, using commercial WiFi and 3G services.     

A Remark on an Example By Teel–Hespanha With Applications to Cascaded Systems

The properties of a system, proposed by Teel and Hespanha, which is globally exponentially stable but with state that can be driven to infinity by an arbitrarily small exponentially decaying disturbance, are discussed in detail. These are used to propose a family of systems with a similar property and to argue that unstable behavior may be nongeneric and not detected by means of simulations. Finally, sufficient conditions for the existence of unbounded trajectories in cascaded systems are given     

A formal approach to the integrated analysis of security and QoS

Concurrent and distributed systems are subject to several requirements of different nature. Among them security and quality of service (QoS) are two fundamental aspects, which can have a profound impact on the system performability. Unfortunately, the study of the tradeoff between security guarantees and performance needs is hard to accomplish, because the related analysis activities are usually carried out separately. In this paper, we present an integrated and tool-supported methodology encompassing both activities, which can provide insights about how to trade the QoS delivered by a system with its security guarantees. The methodology is illustrated by assessing the effectiveness and the efficiency of the securing strategy implemented in the NRL Pump, a trusted device proposed to secure the replication of information from a low-security level enclave to a high-security level enclave.     

SPR-Based Detection of ASF Virus in Cells

African swine fever (ASF) is one of the most dangerous hemorrhagic infectious diseases that affect domestic and wild pigs. Currently, neither a vaccine nor effective treatments are available for this disease. As regards the degree of virulence, ASFV strains can be divided into high, moderate, or low virulence. The main detection methods are based on the use of the polymerase chain reaction (PCR). In order to prevent an uncontrolled spread of ASF, new on-site techniques that can enable the identification of an early-stage disease are needed. We have developed a specific immunological SPR-based assay for ASFV antigen detection directly in liquid samples. The developed assay allows us to detect the presence of ASFV at the dose of 10³ HAD₅₀/_mL.     

Tubing the Future: Participatory Pedagogy and YouTube U in 2020

Our vision for the future of composition focuses on the “tube” and the culture inspired by online video sharing. Understanding composition in 2020 requires further theorizing about the participatory practices occurring in online video culture. Based on practices found on the platform YouTube, we turn to the term “tubing” to explain phenomena taking place there, and we put forward the concept of “participatory pedagogy” that we see emerging in 21st century classrooms. The ubiquitous and historically loaded “tube” (noun) and its YouTube-specific counterpart “tubing” (verb), explain many of the shifts taking place as acts of writing expand to include participation in online video sharing. Other scholars have forwarded the notion of “postpedagogy” (Vitanza, 1991; Davis, 2000; Arroyo, 2003, 2005; Rickert, 2007), which places a high value on invention, encourages the playful, yet serious linking of disparate historical figures, and opens up new pathways that we see as working in tandem with what George Siemens (2005) called a “pedagogy of participation,” an offshoot of what Henry Jenkins named “participatory culture” (2009). Using tubing as a guiding metaphor, we develop our version of “participatory pedagogy” for 2020 by focusing on the propagation of Internet memes and the inventional possibilities found in the everyday practices of video culture, which create an historical archive, an untapped repository of cultural patterns, and a light yet ruthlessly public demand for participation.