Enzo Ferrara

High frequencies are ubiquitous in present-day power applications: most electrical equipment, like rotating machines, are supplied by Pulse Width Modulation (PWM) switching inverters, often working at tens or hundreds of kilohertz. PWM is responsible of minor cycles along the major hysteresis loop of the magnetic core, lasting a few microseconds. S...

We investigate the temperature dependence of the energy loss W(f) of 0.10 and 0.20 mm thick Fe-Co-V sheets (Vacoflux® and Vacodur®) in the range -50 °C ≤ T ≤ 155 °C. The measurements, performed from DC to f = 5 kHz on ring samples and Epstein strips, show that W(f) passes through a minimum value around room temperature at all tested polariz...

When we launched Visions for Sustainability, we wanted to provide a space for as wide a range as possible of ways of looking at the concept of sustainability and at the same time of considering the multiple perspectives from which that concept can shed light on the ecological trajectories of all the biotic and abiotic components of the planet we in...

The magnetic properties of high-permeability grain-oriented (HGO) Fe-Si sheets have been investigated in the frequency range 1 Hz-10 kHz, with attention devoted to the role of thickness on the behavior of the magnetic losses and the phenomenology of skin effect. The study is focused on the wideband response of 0.174 mm and 0.289 mm thick sheets, co...

We investigate the effect of mechanical cutting on the magnetic properties of high permeability grain-oriented (HGO) laser-scribed Fe-Si sheets. Measurements have been performed on strips of different widths (5 to 60 mm) cut from 0.27 mm thick sheets. Normal magnetization curve and energy loss have been determined by means of a digitally controlled...

In this work, we show that the energy losses, measured from 1 Hz to 300 Hz on GO sheets cut along directions ranging from 0° to 90° with respect to RD, can be interpreted in terms of linear composition of the same quantities measured along RD and TD. This feature, which applies to both the DC and AC properties, resides on the sample geometry-indepe...

Magnetization curve and energy losses have been analyzed in non-oriented (NO) Fe-Si alloys with variable thickness (0.20 mm – 0.35 mm), cut at widths ranging between 5 mm and 60 mm, in order to assess the impact of cutting, either done by punching or water-jet techniques. Measurements were performed by means of a digitally controlled single strip t...

Even though multidisciplinary approaches are widely used for the investigation of archaeological findings, magnetic analyses are still little exploited and only rarely applied to the determination of ancient artefacts use. Here, we present the results of a combined archaeological, morphological, and magnetic study carried out on the ring-shaped cla...

Comprehensive assessment of the magnetic behavior of grain-oriented steel (GO) Fe–Si sheets, going beyond the conventional characterization at power frequencies along the rolling direction (RD), can be the source of much needed information for the optimal design of transformers and efficient rotating machines. However, the quasi-monocrystal charact...

Synthesis of the dependence on sample geometry of the evolution of the domain structure in GO sheets cut at 45° to the Rolling Direction

This article looks at life as biolanguaging and how the sustainability of life itself depends on language as a means of creating the flow, the exchange and the processing of information that enable the biological processes that are vital for all living organisms.

We present new insights on the directional occurrence of the Levantine Iron Age Anomaly (LIAA) through the analysis of new and previously published directional archaeomagnetic data from Cyprus and nearby countries. The new directions, obtained from in situ baked clay structures such as small hearths and ovens from five Cypriot archaeological sites,...

We investigate in theory and experiment the frequency dependence of magnetic losses in Grain-Oriented 0.29 mm thick high-permeability steel sheets up to 10 kHz. Such an unusually broad frequency range, while responding to increasing trends towards high-frequency regimes in applications, is conducive to a complex evolution of the magnetization proce...

Objectives Little evidence is available on the role of transcranial direct current stimulation (tDCS) in patients affected by chronic migraine (CM) and medication overuse headache (MOH). We aim to investigate the effects of tDCS in patients with CM and MOH as well as its role on brain activity. Methods Twenty patients with CM and MOH were hospital...

An experimental method to characterize the electromagnetic properties of tattoo inks is proposed. The overall procedure is aimed to investigate possible safety implications related with Magnetic Resonance Imaging (MRI). In this work, the experimental analysis is demonstrated on five commercial different tattoo inks. Measurements have been carried o...

Magnetization curve and energy losses have been analyzed in non-oriented (NO) Fe-Si alloys with variable thickness (0.20 mm–0.35 mm), cut at widths ranging between 5 mm and 60 mm, in order to assess the impact of cutting, either done by punching or water-jet techniques. Measurements were performed by means of a digitally controlled single strip tes...

Grain-oriented (GO) Fe-Si sheets are often preferred to non-oriented steels in large rotating machines, where the material response along different di- rections from the rolling one (RD) matters, both in terms of magnetisation curve and energy losses. The experiments show that the material properties depend in a complex fashion on the angle θ made...

Magnetic mineral inclusions, as iron oxides or sulfides, occur quite rarely in natural diamonds. Nonetheless, they represent a key tool not only to unveil the conditions of formation of host diamonds, but also to get hints about the paleointensity of the geomagnetic field present at times of the Earth’s history otherwise not accessible. This possib...

Magnetic mineral inclusions, as iron oxides or sulfides, occur quite rarely in natural diamonds. Nonetheless, they represent a key tool not only to unveil the conditions of formation of host diamonds, but also to get hints about the paleointensity of the geomagnetic field present at times of the Earth’s history otherwise not accessible. This possib...

Reconstructing the distribution of ancient obsidian tools is one of the few ways to trace ancient trade routes during the Neolithic. The use of magnetic properties for obsidian provenance studies has already been applied as a useful inexpensive and non-destructive tool. It is mainly based on the variation of the type, concentration and grain size o...

The Preisach model of hysteresis is applied to interpret the experimental behaviour of hysteresis loop and First Order Reversal Curves (FORCs) collected on sub-mm size, Fe-rich magnetic inclusions entrapped in 4 natural diamonds. In particular, the Preisach distribution is decomposed in the sum of a reversible and irreversible term, with the former...

Magnetic mineral inclusions, as iron oxides or sulfides, occur quite rarely in natural diamonds. Nonetheless, they represent a key tool not only to unveil the conditions of formation of host diamonds, but also to get hints about the paleointensity of the geomagnetic field present at times of the Earth's history otherwise not accessible. This possib...

Experimental and theoretical results are presented on the magnetic properties of magnetite/magnesioferrite polycrystalline inclusions trapped in natural diamonds. In particular, hysteresis loops and First Order Reversal Curves (FORCs) -detected with an Alternating Gradient Field Magnetometer- are qualitatively interpreted in terms of the magnetic...

Faster switching for soft magnets The most familiar magnets are permanent magnets like the ones on a refrigerator door. However, for applications in transformers and motors, soft magnets that can rapidly switch their magnetization in response to a magnetic field are used. In electronics, wide bandgap semiconductors such as silicon carbide will allo...

Efficient applications of magnetic cores in sensing and power electronics require low-loss and versatile soft magnetic materials, with excellent response on a wide range of frequencies. This objective is traditionally pursued with ferrite and Permalloy tape cores, available under a variety of properties. Comparable and even superior soft magnetic b...

We present new experimental results on the variation of the magnetic properties of baked clays as a function of the temperature reached during laboratory treatments. Such experiments, including continuous monitoring of the magnetic susceptibility and magnetic moment versus temperature, were applied to a set of natural clays experimentally heated in...

We present a new sedimentological profile and a magnetostratigraphy of the tool-bearing Kozarnika cave sediments from Bulgaria. Modal analysis of cave infilling sedimentary texture indicates that the tool-bearing layers contain a sizable fraction of sediment interpreted as loess. We also find evidence for a relatively thick and well defined normal...

This paper concerns the sensing of dynamic force/stress by means of a measuring system based on the use of an Fe-Ga sample (Galfenol) coupled to a magnetic circuit. The study is focused on the measurement of the effective magnetic field, detected at the rod specimen surface, and its variation DeltaHeff under time-dependent applied sinusoidal stress...

Effect of yttrium on glass-forming ability (GFA), thermal stability and mechanical properties of glassy Fe-Cr-Mo-C-B-Yalloy were studied. Amorphous alloys with composition (at %) Fe48Cr15Mo14C15B6Y2 were prepared by usinga commercial AISI430 steel as a base material. In the case of a bulk metallic glass (BMG), are prepared by usingcommercial grade...

The magnetic power losses have been measured at 50 Hz and different peak polarization values on different types of non-oriented and grain-oriented Fe-Si sheets using the Epstein frame, according to the current standards. The very same measurements have then been repeated by measuring polarization and tangential magnetic field by means of localized...

This paper collects notes and reflections emerging from the survey of three volumes published in the Earth System Governance MIT Press series, dealing with issues of world politics, international institutions, consensus, deliberative democracy, and leadership of global governance in the dawn of the Anthropocene. The gathering arguments of the texts...

We present new, full geomagnetic field vector results from three Neolithic ovens discovered at the archaeological site of Portonovo (Marche, Italy). The discovered structures are a rare example of very well preserved underground ovens from the Early Neolithic period. Standard thermal demagnetization procedures were used to isolate the direction of...

Finemet type alloys have been investigated from DC to 1 GHz at different induction levels upon different treatments: as amorphous precursors, as ribbons nanocrystallized with and without an applied saturating field, as consolidated powders. The lowest energy losses at all frequencies and maximum Snoek's product are exhibited by the transversally fi...

Book Review: The Ecology of Law. Toward a Legal System in Tune with Nature and Community, by Fritjof Capra, and Ugo Mattei, Berrett-Koheler Publishers, Oakland (CA) 2015

Originally Published as Rachel Louise Carson (1937). Undersea. Atlantic Monthly, 78:55–67

The manifesto of our new international scientific journal: Visions for Sustainability.

We discuss the results of an international comparison regarding the measurement of magnetic power loss and apparent power between 20 Hz and 100 Hz at magnetic polarization values ranging between 1.3 T and 1.8 T in grain-oriented steel (GO) sheets using the Single Sheet Testing (SST) and Epstein methods. This exercise, carried out in the framework o...

editorial

We present a detailed rock-magnetic and archaeomagnetic study of two brick kilns, named OSA and OSB, discovered at the location of Osterietta, in northern Italy. The magnetic properties of representative samples have been investigated to identify the nature of the magnetic carriers, their domain state and thermal stability, and investigate their su...

Bricks, fine pottery, ceramic gears and tiles are among the human-made objects routinely recovered in archaeological documentation. Sites associated with early civilizations can provide thousands of samples from a single excavation. They come in endless varieties according to economic and social circumstances and, as debris can last almost forever,...

A magnetic damping system for nanospacecraft attitude stabilization is proposed, based on the use of thin strips of amorphous Fe-B-Si soft magnetic ribbons. The size, number, and location of the strips is optimized, and a predictive formulation is provided. The main result of ground tests, comparing the performance of several soft magnetic material...

Combining different dating techniques is fundamental to constrain the ages of archaeological findings, mainly when direct evidences for their chronological context are not available. This paper presents the results of a combined archaeological, archaeomagnetic and thermoluminescence study of a kiln discovered during a rescue excavation at Chieri, n...

Broadband magnetic loss and damping behavior of Co-based amorphous ribbons and thin films have been investigated. The permeability and loss response of the transverse anisotropy ribbon samples in the frequency range DC to 1 GHz is interpreted in terms of combined and distinguishable contributions to the magnetization process by domain wall displace...

Fe-based bulk metallic glasses (BMGs) have been extensively studied due to their potential technological applications and their interesting physical and mechanical properties such as a low modulus of elasticity, high yielding stress and good magnetic properties. In the present work, theamorphous ribbonformation of Fe40Ni40B20 (numbers indicate at....

Modern Science, an essay written by Lev Nikolàevič Tolstoy in 1898 is here reproduced in its complete version, as a historical document containing philosophical reflections on the practical functions and the cultural and educational role science has, or should have, in contemporary societies. The text was cited by Aldous Huxley in the foreword to S...

We have investigated and modeled the magnetization process in thin amorphous and nanocrystalline ribbons from DC to 1 GHz. These transverse anisotropy laminations, their thickness ranging between 6 and 20 m, display excellent broadband magnetic behavior, ensuing from the dominant role of magnetization rotations. Combination of fluxmetric, aftereffe...

The potential of magnetic grain-size variations as an obsidian source characteristic is investigated using geological and archaeological obsidians from five islands of the Mediterranean Sea: Lipari, Sardinia, Palmarola, Pantelleria, Melos. Four parameters are used: magnetic (χ) and anhysteretic (χa) susceptibilities, saturation isothermal remanent...

Amorphous and nanocrystalline ribbons with transverse anisotropy have been characterized by magneto-optical, fluxmetric, and transmission line techniques from DC to 1 GHz. The contributions of domain wall displacements and magnetization rotations to the magnetization process, singled out by direct domain observations, consistently fit with the obse...

The magnetization process in field annealed amorphous ribbons has been investigated from dc to 10 MHz. Loss and permeability measurements, carried out both on single strips and ring samples by means of a broadband fluxmetric setup, have been associated with observations of the domain wall dynamics by high-speed stroboscopic Kerr apparatus. Transver...

Science Fiction Studies is an academic journal, vibrantly engaged with critical and cultural theories, published three times a year at DePauw University (Indiana). Its issues deal with what is considered the most popular genre of contemporary literature. Since the middle of the 20th century, in fact, science fiction (SF) continues to exert an enorm...

Significant results are reported concerning the magnetic behavior of sintered soft ferrites and very thin Co-based amorphous ribbons up to 1 GHz. Conveniently field-annealed amorphous tapes can exhibit, in spite of their metallic character, superior combination of magnetic loss and permeability properties at all frequencies. Such properties are phe...

Significant results are reported concerning the magnetic behavior of sintered soft ferrites and very thin Co-based amorphous ribbons up to 1 GHz. Conveniently field-annealed amorphous tapes can exhibit, in spite of their metallic character, superior combination of magnetic loss and permeability properties at all frequencies. Such properties are phe...

The spinning and oscillatory motions of small orbiting satellites can be damped exploiting the magnetic energy dissipation occurring in onboard soft magnetic strips, cyclically excited by the oscillation of the earth field component along their axis. In this paper we investigate the role played by the intrinsic magnetic properties of the material,...

Although they concentrate their respective attentions on supposedly separate issues—the human factor, environmental catastrophes and rising consumerism in developing countries—the questions raised by this set of documentaries are strictly intertwined. The viewpoint can move from Denmark to the Southern U.S.A. or China, but the focus remains on the...

Permeable rods have been used in passive magnetic attitude stabilization systems since the beginning of space era, as an efficient means to damp out the satellite angular velocity and residual spacecraft oscillatory motion. A new interest in these kinds of systems has arisen with the nanosatellites coming on the space market and the advent of small...