Dynamic hysteresis in Finemet thin films

We performed a series of dynamic hysteresis measurements on three series of Finemet films with composition Fe$_{73.5}$Cu$_1$Nb$_3$Si$_13.5$B$_9$, using both the longitudinal magneto-optical Kerr effect (MOKE) and the inductive fluxometric method. The MOKE dynamic hysteresis loops show a more marked variability with the frequency than the inductive ones, while both measurements show a similar dependence on the square root of frequency. We analyze these results in the frame of a simple domain wall depinning model, which accounts for the general behavior of the data.Comment: 3 pages, 3 figure

A nonparametric approach for model individualization in an artificial pancreas

The identification of patient-tailored linear time invariant glucose-insulin models is investigated for type 1 diabetic patients, that are characterized by a substantial inter-subject variability. The individualized linear models are identified by considering a novel kernel-based nonparametric approach and are compared with a linear time invariant average model in terms of prediction performance by means of the coefficient of determination, fit, positive and negative max errors, and root mean squared error. Model identification and validation are based on in-silico data collected from the adult virtual population of the UVA/Padova simulator. The data generation involves a protocol designed to produce a sufficient input excitation without compromising patient safety, compatible also with real life scenarios. The identified models are exploited to synthesize an individualized Model Predictive Controller (MPC) for each patient, which is used in an Artificial Pancreas to maintain the blood glucose concentration within an euglycemic range. The MPC used in several clinical studies, synthesized on the basis of a non-individualized average linear time invariant model, is also considered as reference. The closed-loop control performance is evaluated in an in-silico study on the adult virtual population of the UVA/Padova simulator in a perturbed scenario, in which the MPC is blind to random variations of insulin sensitivity in each virtual patient. © 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved

Fast model predictive control for hydrogen outflow regulation in ethanol steam reformers

© 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In the recent years, the presence of alternative power sources, such as solar panels, wind farms, hydropumps and hydrogen-based devices, has significantly increased. The reasons of this trend are clear: contributing to a reduction of gas emissions and dependency on fossil fuels. Hydrogen-based devices are of particular interest due to their significant efficiency and reliability. Reforming technologies are among the most economic and efficient ways of producing hydrogen. In this paper we consider the regulation of hydrogen outflow in an ethanol steam reformer (ESR). In particular, a fast model predictive control approach based on a finite step response model of the process is proposed. Simulations performed using a more realistic non-linear model show the effectiveness of the proposed approach in driving the ESR to different operating conditions while fulfilling input and output constraints.Peer ReviewedPostprint (author's final draft

Individual attitude toward improvisation in information systems development: a multi-level perspective

Improvisation is rapidly becoming an important issue for both scholars and practitioners. Organizations that operate in turbulent environments must learn to swiftly adapt and respond to such instability, especially in areas as innovation and new product development. In such contexts traditional top-down, carefully-planned approaches to innovative projects may represent an obstacle to effectively dealing with environment uncertainty. Prior research on improvisation has focused considerable attention on the centrality of improvisation in individual and group outcomes, while less emphasis has been placed on how individual attitude toward improvisation is formed. In an attempt to fill this gap, we will theoretically analyze the antecedents of individual attitude toward improvisation, by looking at the Information Systems Development (ISD) domain. In particular, the outcome of this paper is the development of theoretical propositions which could be empirically tested in future research

Artificial Pancreas: In Silico Study Shows No Need of Meal Announcement and Improved Time in Range of Glucose with Intraperitoneal vs. Subcutaneous Insulin Delivery

Contemporary Artificial Pancreas (AP) consists of a subcutaneous (SC) glucose sensor, a SC insulin pump and a control algorithm. Even the most advanced systems are far from optimal, in particular due to the non-physiologic nature of SC route. While SC insulin delivery is convenient and minimally invasive, it introduces delays to insulin action that make tight control difficult, particularly during meals. In addition frequent patient interventions are needed, e.g., at mealtime. The intraperitoneal (IP) insulin delivery could address this major challenge since it exhibits a faster pharmacokinetics/pharmacodynamics, hence making easier to quickly respond to glycemic disturbances. A 1-day hospital closed-loop study has shown significant improvements of IP glucose control vs SC AP, and that meal announcement is not necessary. However, the IP AP has not been tested in more realistic everyday life conditions. In this work we have performed an in silico study of 14 days of an IP AP by using the UVA/Padova simulator which includes intra- and inter-day variability of insulin sensitivity and several real life scenarios. We show superiority of IP AP vs SC AP in terms of quality of glucose control (time in range 87% IP vs 80% SC) without the need of a meal announcement

Gli insetti al servizio degli inquirenti

Per molti anni gli insetti che popolavano la superficie e gli orifizi dei cadaveri sono stati considerati solo una presenza poco gradevole del lavoro dei medici legali e delle Forze dell'Ordine coinvolte nelle indagini inerenti a crimini violenti. Ma come gli intriganti romanzi di Deawer e della Cornwell ci hanno insegnato, gli insetti costituiscono dei silenziosi custodi di preziosi informazioni sull'accadimento di fatti a volte inspiegabili. Tuttavia mentre le varie branche delle scienze criminalistiche (la biologia, la balistica, la chimica, ecc.) hanno avuto nel tempo una crescita esponenziale, affinando tecniche e metodologie, lo studio degli insetti associati alla scena criminis è stato, nel nostro Paese per molto tempo sottovalutato o addirittura ignorato. L'Entomologia Forense è un ramo della zoologia dedicata allo studio degli insetti e di altri artropodi, dal cui esame è possibile ricavare elementi decisivi per la persecuzione di un reato. Negli ultimi anni tale disciplina ha visto crescere l'interesse da parte degli scienziati forensi, dei Medici Legali e delle Forze dell'Ordine, soprattutto in Europa e negli USA, dove esistono figure professionali specialistiche che affiancano la magistratura inquirente nella risoluzione di casi di morti sospette ed altri reati accomunati dalla presenza di insetti. Purtroppo in Italia solo da pochi anni si è sviluppato l'interesse verso la materia e ancora oggi gli entomologi forensi non lavorano sistematicamente accanto agli organi di Giustizia. Lo scopo del presente lavoro è una disamina delle potenzialità dell'Entomologia Forense e delle relative applicazioni come strumento spesso determinante per la risoluzione di intriganti e complessi casi giudiziari

Is demagnetization an efficient optimization method?

Demagnetization, commonly employed to study ferromagnets, has been proposed as the basis for an optimization tool, a method to find the ground state of a disordered system. Here we present a detailed comparison between the ground state and the demagnetized state in the random field Ising model, combing exact results in $d=1$ and numerical solutions in $d=3$. We show that there are important differences between the two states that persist in the thermodynamic limit and thus conclude that AC demagnetization is not an efficient optimization method.Comment: 2 pages, 1 figur

Investigation of scaling properties of hysteresis in Finemet thin films

We study the behavior of hysteresis loops in Finemet Fe$_{73.5}$Cu$_1$Nb$_3$Si$_{18.5}$B$_4$ thin films by using a fluxometric setup based on a couple of well compensated pickup coils. The presence of scaling laws of the hysteresis area is investigated as a function of the amplitude and frequency of the applied field, considering sample thickness from about 20 nm to 5 $\mu$m. We do not observe any scaling predicted by theoretical models, while dynamic loops show a logarithmic dependence on the frequency.Comment: 2 pages, 2 figure