Asymptotic solitons of the Johnson equation

We prove the existence of non-decaying real solutions of the Johnson equation, vanishing as $x\to+\infty$. We obtain asymptotic formulas as $t\to\infty$ for the solutions in the form of an infinite series of asymptotic solitons with curved lines of constant phase and varying amplitude and width

Entanglement generation in relativistic cavity motion

We analyse particle creation and mode mixing for a quantum field in an accelerated cavity, assuming small accelerations but allowing arbitrary velocities, travel times and travel distances, and in particular including the regime of relativistic velocities. As an application, we identify a desktop experimental scenario where the mode mixing resonance frequency in linear sinusoidal motion or in uniform circular motion is significantly below the particle creation resonance frequencies of the Dynamical Casimir Effect, and arguably at the threshold of current technology. The mode mixing acts as a beamsplitter quantum gate, experimentally detectable not only via fluxes or particle numbers but also via entanglement generation.Comment: 8 pages, LaTeX with jpconf. Submitted to DICE2012 proceeding

Finite element simulation of semi-finishing turning of Electron Beam Melted Ti6Al4V under dry and cryogenic cooling

open6noIn the last few years, important step forwards have been made on Finite Element Simulation of machining operations. Wrought Ti6Al4V alloy has been deeply investigated both numerically and experimentally due to its wide application in the industry. Recently, Additive Manufacturing technologies as the Electron Beam Melting and the Direct Melting Laser Sintering are more and more employed in the production of biomedical and aeronautical components made of Ti6Al4V alloy. Fine acicular microstructures are generated by the application of additive manufacturing technologies, affecting the mechanical properties and the machinability. By the consequence, this peculiarity has to be considered in modelling the material behaviour. In this work, a numerical analysis of cylindrical external turning on Electron Beam Melted (EBM) Ti6Al4V alloy is presented. A Johnson-Cook constitutive equation was implemented as a flow stress model and adapted with respect to the wrought Ti6Al4V alloy. The model was calibrated and validated through the cutting forces and temperatures measurements acquired under dry and cryogenic lubricating conditions.openBordin, A; Imbrogno, S.; Rotella, G.; Bruschi, S.; Ghiotti, A.; Umbrello, D.Bordin, Alberto; Imbrogno, S.; Rotella, G.; Bruschi, Stefania; Ghiotti, Andrea; Umbrello, D

Use of biodiversity hotspots for conservation of Marine Molluscs: a regional approach

A method to define biodiversity hot spots as regards marine molluscs is proposed. Species richness of Italian marine molluscs is analysed by means of data collected by members of the Italian Malacological Society. Data are ordered in the database 'Census of Italian Marine Molluscs' available on the Internet. The Census contains about 20.000 records concerning 901 species sampled in 663 localities around all the Italian coasts. The records are divided into 59 lots; for each lot we formulate an index of species richness not related to the sampling effort. This index shows a positive correlation with the environmental diversity and with the proportion of hard substrates on the sea bottom. In the lots we assess the distribution of species worth of protection (according to literature) and of most rare species. Combining these data with the distribution of lots with higher values of species richness index, we identify hot spots available for conservation

Analysis of non-compliances in the organic certification system in Turkey.

ABSTRACT: Organic farming in Turkey is experiencing a strong growth in recent years, with a particular attention to export towards Europe. International and domestic trade opportunities require an efficient control system for organic products. In this paper we analyse the data from inspections of two European control bodies in Turkish farms to analyse risk patterns of non-compliance with the organic regulation. A proportion test is performed to identify the types of crops that are more likely related to non-compliant operators

Efficient Hardware Design Of Iterative Stencil Loops

A large number of algorithms for multidimensional signals processing and scientific computation come in the form of iterative stencil loops (ISLs), whose data dependencies span across multiple iterations. Because of their complex inner structure, automatic hardware acceleration of such algorithms is traditionally considered as a difficult task. In this paper, we introduce an automatic design flow that identifies, in a wide family of bidimensional data processing algorithms, sub-portions that exhibit a kind of parallelism close to that of ISLs; these are mapped onto a space of highly optimized ad-hoc architectures, which is efficiently explored to identify the best implementations with respect to both area and throughput. Experimental results show that the proposed methodology generates circuits whose performance is comparable to that of manually-optimized solutions, and orders of magnitude higher than those generated by commercial HLS tools

Detecting (Absent) App-to-app authentication on cross-device short-distance channels

Short-distance or near-field communication is increasingly used by mobile apps for interacting or exchanging data in a cross-device fashion. In this paper, we identify a security issue, namely cross-device app-to-app communication hijacking (or CATCH), that affect Android apps using short-distance channels (e.g., Bluetooth and Wi-Fi-Direct). This issue causes unauthenticated or malicious app-to-app interactions even when the underlying communication channels are authenticated and secured. In addition to discovering the security issue, we design an algorithm based on data-flow analysis for detecting the presence of CATCH in Android apps. Our algorithm checks if a given app contains an app-to-app authentication scheme, necessary for preventing CATCH. We perform experiments on a set of Android apps and show the CATCH problem is always present on the whole analyzed applications set. We also discuss the impact of the problem in real scenarios by presenting two real case studies. At the end of the paper we reported limitations of our model along with future improvements

Computational approaches to shed light on molecular mechanisms in biological processes

Computational approaches based on Molecular Dynamics simulations, Quantum Mechanical methods and 3D Quantitative Structure-Activity Relationships were employed by computational chemistry groups at the University of Milano-Bicocca to study biological processes at the molecular level. The paper reports the methodologies adopted and the results obtained on Aryl hydrocarbon Receptor and homologous PAS proteins mechanisms, the properties of prion protein peptides, the reaction pathway of hydrogenase and peroxidase enzymes and the defibrillogenic activity of tetracyclines. © Springer-Verlag 2007

Geon black holes and quantum field theory

Black hole spacetimes that are topological geons in the sense of Sorkin can be constructed by taking a quotient of a stationary black hole that has a bifurcate Killing horizon. We discuss the geometric properties of these geon black holes and the Hawking-Unruh effect on them. We in particular show how correlations in the Hawking-Unruh effect reveal to an exterior observer features of the geometry that are classically confined to the regions behind the horizons.Comment: 11 pages. Talk given at the First Mediterranean Conference on Classical and Quantum Gravity, Kolymbari (Crete, Greece), September 2009. Dedicated to Rafael Sorkin. v2: typesetting bug fixe

Recognition and Assessment of Geomorphosites in Malta at the Il-Majjistral Nature and History Park

The Il-Majjistral Nature and History Park, located on the northwestern coast of the Island of Malta, is a protected area with natural, cultural and tourist interests. The Park, which was registered in 2008, is characterised by a landscape dominated by limestone and clay. Geomorphological features are highly controlled by the presence of faults and rock masses characterised by different physical and mechanical properties. Coastal cliffs, bays and sandy beaches are the most outstanding geomorphological features of the Park, creating a breathtaking landscape which is an attraction for a number of visitors. In the framework of an international research project, a study for the identification, selection and enhancement of the rich geomorphological heritage of the area has been carried out. In particular, a recognition and a quantitative assessment of geomorphosites on the basis of two different methodologies has been developed, and the results have been compared to establish the reliability of the methodologies. The results represent the first step and the necessary basic knowledge for possible enhancement of geomorphosites in Malta and the promotion of tourism activities at the Il-Majjistral Nature and History Park through the auspices of environmental agencies