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NiMnGa Heusler alloy plays a key role as reference system for ferromagnetic shape memory alloys (FeSMAs) and their peculiar functional properties including large magnetic-field-induced strain, magnetocaloric and elastocaloric effects. Moreover, the microstructure of polycrystalline NiMnGa alloys has been investigated and optimized to improve the mechanical properties and to reduce their typical brittleness. For this reason, increasing interest has been devoted to different kinds of fabrication routes for this alloy, such as powder metallurgy processes. In the present study, a polycrystalline Ni50Mn30Ga20 (atomic %) alloy is produced by means of an unconventional sintering method that involves the canning of powders and the subsequent processing by hot rolling. This process was implemented according to the results obtained by means of the open die pressing (ODP) sintering of NiMnGa which was investigated in a previous work. The present study is aimed at developing an alternative and cost-effective sintering method for the consolidation of fully-dense NiMnGa samples. The process allowed reducing the intrinsic brittleness of the alloy. A heat treatment at 925 °C for 6 h was applied and allowed achieving a maximum adiabatic ΔT of +6.3 °C and - 4.5 °C with a strain of 4 % and a strain rate of 400 %/min in compression. The novel method led to very promising elastocaloric properties, making NiMnGa a suitable candidate for solid-state cooling and heating applications.

Suitable families of random variables having power series distributions are considered, and their asymptotic behavior in terms of large (and moderate) deviations is studied. Two examples of fractional counting processes are presented, where the normalizations of the involved power series distributions can be expressed in terms of the Prabhakar function. The first example allows to consider the counting process in [Integral Transforms Spec. Funct. 27 (2016), 783–793], the second one is inspired by a model studied in [J. Appl. Probab. 52 (2015), 18–36].

The major part of solid-state transformations modeling has concentrated on transformations taking place from a homogeneous matrix. Nonetheless, there are situations in which one finds an inhomogeneous matrix. An example is the recrystallization of metals subjected to an inhomogeneous deformation. If the recrystallization takes place in the regions where the stored energy of cold work is high, one has both a higher number of nuclei and faster growth velocity than in the region where the stored energy is low. In this work, we conduct computer simulations of transformations of a matrix possessing inhomogeneous nucleation and growth. We compare the computer simulations with an analytical solution that considers at the same time both the variation of the number of nuclei and the velocity. These results are compared with results obtained when only inhomogeneous nucleation is considered, whereas the velocity is kept constant throughout the matrix. For the number of nuclei and velocity gradients used here the main simulation results were: a) the inhomogeneous velocity does have a substantial effect on the transformation kinetics and microstructural evolution, b) the inhomogeneous distribution of nuclei has a more significant impact on the microstructure than an inhomogeneous distribution of velocity

Shape memory alloys (SMAs) and ferromagnetic shape memory alloys (FeSMAs) have recently attracted interest for solid state refrigeration applications. Among NiMnGa-based quaternary systems, NiMnGaCu exhibits an interesting giant magnetocaloric effect thanks to the overlapping of the temperatures related to the magnetic transition and the thermoelastic martensitic transformation (TMT); in particular, for compositions with Cu content of approximately 6 at%. In the present work, we investigated the improvement effect of TMT on the total entropy change (ΔS) in the elastocaloric performances of polycrystalline Ni50Mn18.5Cu6.5Ga25 at% alloy samples, just above room temperature. We report an extensive calorimetric and thermomechanical characterization to explore correlations between microstructural properties induced by the selected thermal treatment and elastocaloric response, aiming at providing the basis to develop more efficient materials based on this quaternary system. Both ΔT and ΔS values obtained from mechanical curves at different temperatures and strain recovery tests under fixed load vs. T were considered. Maximum values of ΔS = 55.9 J/KgK and ΔT = 4.5 K were attained with, respectively, a stress of 65 MPa and strain of 4%. The evaluation of the coefficient of performance (COP) was carried out from a cyclic test.

A considerable number of engineering materials is polycrystalline. Cahn proposed analytical expressions for transformations nucleated at the grain faces, triple junctions, and quadruple junctions. Those places are usually the places in which a new phase takes place. Cahn assumed that the new grain boundary nucleated phase grew as spheres. Nonetheless, the austenite grain boundary nucleated ferrite does not always grow as spheres. Bradley et al. demonstrated in a series of papers that a grain boundary nucleated ferrite allotriomorph is best described by an oblate ellipsoid. The reason for ellipsoidal growth is that the growth along the grain boundary plane is faster than the thickening into the austenite. Because of this, it is of interest to have analytical solutions and computer simulations of grain boundary nucleated transformations not only for spherical growth but also for ellipsoidal growth. In this work, we present a computer simulation of grain boundary nucleated transformations that grow as ellipsoids. The computer simulation results were compared with a new exact analytical expression obtained by Villa and Rios.

Among NiTi-based alloys, one of the most promising and exploited alloys is NiTiCu, since the addition of Cu in substitution of Ni in the binary equiatomic NiTi has a significant influence on the martensitic transformation and the thermomechanical properties of the system. A high content of Cu improves the damping properties at the expense of phase homogeneity and workability. The present study focuses on an alloy with a high copper content, i.e., 20 at.%. For this specific composition, the correlation between the thermal treatments, microstructure, formation of secondary phases, and damping properties are investigated by several analyses. The microscopic observation, together with the compositional analysis, allowed the determination of four different phases in the alloy. Both the calorimetry and dynamic thermo mechanical measurements, which confirmed the high damping ability of the alloy, provided a characterization of the martensitic transition. Finally, the electron backscatter diffraction (EBSD) analysis detected the different crystallographic structures (i.e., cubic austenite, orthorhombic martensite, and cubic (face-centered) NiTi2) and their orientation in the different phases. Therefore, the present work aims to improve the knowledge of the role of secondary phases in the optimization of the NiTiCu20 alloy as a valuable alternative to typical alloys used for damping purposes.

The superelastic properties and stress-induced martensite (SIM) stabilization have been studied in a shape memory Ni51.1Fe16.4Ga26.3Co6.2 single crystal. The single crystal, characterized by a thermally induced forward martensitic transformation temperature around 56 °C in the initial state, has been submitted to compression mechanical testing at different temperatures well above, near and below the martensitic transformation (MT). After each mechanical test, the characteristic MT temperatures and the transformation enthalpy have been monitored by means of differential scanning calorimetry. At temperatures below MT, the stress–strain (σ–ε) curves show a large strain, around 6.0%, resulting from the detwinning process in the martensitic microstructure, which remains accumulated after unloading in the detwinned state of the sample as a typical behavior of the shape memory alloys (SMAs). After just two “σ–ε + heating” cycles the accumulation of strain was not observed any more indicating the formation of a two-way shape memory effect which consists in a spontaneous recovery of the aforementioned detwinned state of the sample during its cooling across the forward MT. Whereas the thermally induced shape recovery in conventional SMAs occurs at the fixed value of the reverse MT temperature, the heating DSC curves of the mechanically deformed martensite in the present work show a burst-like calorimetric peak at the reverse MT arising at temperatures essentially higher than the thermally activated one. This behavior is the result of the SIM stabilization effect. After a short thermal aging in the stress-free state, this effect almost disappears, showing a slight impact on the MT characteristic temperatures and the enthalpy. At temperatures higher than the transformation one, the SIM is not stabilized, as the mechanically induced martensite fully retransforms into austenite after the unloading. From the σ–ε curves, the critical stress, σc, as well as the values of Young’s moduli of martensite and austenite are determined showing linear dependences on the temperature with a slope of 3.6 MPa/°C.

This paper generalizes previous work of Rios and Villa on spherical growth. The generalized equation applies to nucleation of ellipsoids according to an inhomogeneous Poisson point process. Microstructural evolution in three dimensions of nucleation and growth transformations of ellipsoids is simulated using the causal cone method. In the simulation, nuclei are located in space according to an inhomogeneous Poisson point process. The transformed regions grow with prolate and oblate ellipsoidal shapes. The ellipsoids have their corresponding axes parallel. The simulation and the exact analytical solution are in excellent agreement. Microstructures generated by the computer simulation are displayed. From these generated microstructures one can obtain the contiguity. In the contiguity against volume fraction plot, data from the sphere and all ellipsoids fall on the same curve. The contiguity curve for nucleation according to an inhomogeneous Poisson point process falls above the contiguity curve for nucleation according to a homogeneous Poisson point process. This behavior indicates that nucleation according to an inhomogeneous Poisson point process introduced a nucleus clustering effect.

Il lavoro cerca di analizzare le caratteristiche linguistiche e testuali dei pannelli di sala dei Musei. L’analisi è stata svolta seguendo un approccio di tipo orizzontale. Il testo è stato indagato secondo una modalità gerarchica considerando i quattro livelli di analisi caratteristici dei linguaggi settoriali: la morfologia, la sintassi, il lessico e la testualità.Sono stati esaminati casi particolari di pannelli esplicativi, cioè quelli che introducono alle prime sei sale del Museo del Novecento di Milano; inoltre sono stati forniti degli esempi concreti a supporto dell’analisi linguistica e la trascrizione effettiva dei testi presi in esame al fine di dare maggiore esaustività al lavoro.Si è infine sottoposto il campione testuale scelto a due classi di studenti universitari stranieri appartenenti ai progetti Socrates Erasmus e Marco Polo, per testarne l’effettiva comprensibilità da parte di quelli che potrebbero essere potenziali visitatori. Gallery panels in the Museo del 900: linguistic and textual featuresThe paper analyzes the linguistic and textual gallery panels at the Museo del 900. The analysis was carried out using a horizontal approach. The text was investigated considering the four hierarchical levels of analysis for specialized language: morphology, syntax, vocabulary and textuality. The explanatory gallery panels that introduce the first six halls of the Museo del Novecento in Milan were examined. Specific examples support the linguistic analysis as well as the actual transcript of the texts examined. The sample text was submitted to two groups of foreign university students (participants in the Socrates Erasmus and Marco Polo projects) in order to test its understandability by subjects who could be potential visitors.

The present work focused on the microstructural, thermal, electrical, and damping characterization of NiMnGa samples produced through a powder pressing and a sintering process; the effect of sintering times and of the starting powder size were evaluated. Moreover, an observation of the evolution of martensitic transformation typical of NiMnGa ferromagnetic shape memory alloy was conducted in comparison with the cast material behavior and in correlation with the material densification. The optimum powder size and sintering time for the process, i.e., 50 µm or lower and 72 h, were identified considering the investigated physical properties of the sintered samples in comparison to the cast material. The corresponding sample showed the best compromise between density, thermal and electrical properties, and damping and functional behaviour. In general, the outcomes of this study could be the basis of a useful tool for production processes that include a sintering step as well as being a starting point for the evaluation of an alternative low cost fabrication method of this alloy.

Il lavoro cerca di sottolineare l’importanza dell’apparato para-testuale che accompagna le opere d’arte; in particolare sono state esaminate la struttura linguistica e le caratteristiche della didascalia. In primo luogo è stata analizzata brevemente la lingua della storia dell’arte, organizzando un’indagine di tipo linguistico condotta secondo quelli che sono considerati i tre livelli di analisi caratteristici delle lingue speciali: il lessico, la morfosintassi e la testualità. In secondo luogo, si è scelto di approfondire le caratteristiche dell’apporto para-testuale, fornendo un’analisi completa della didascalia e alcune notizie di tipo storico. In terzo luogo si sono esaminati casi particolari di didascalie; nello specifico, sono state scelte quelle che accompagnano i dipinti presenti nelle prime cinque sale del Museo del 900 a Milano e sono stati forniti degli esempi concreti a supporto dell’analisi linguistica. Linguistic characteristics of captions in art, a study case: the: Milan’s Museo del 900 (Museum of the Twentieth Century)Elena VillaThe aim of this work was to emphasize the importance of paratextual apparatus with which artworks are presented; in particular, the author analyzed the linguistic structure and the specific characteristics of captions. First of all, in order to briefly analyze the language of art history, linguistic research was conducted. It built on what are considered to be the three main levels of analysis when jargons is concerned: lexicon, morphosyntax and textuality. Secondly, the author chose to examine in depth the characteristics of the paratextual contribution, by making a complete analysis of captions and giving historical information. Thirdly, the author provided concrete examples of captions to support his previous linguistic observation choosing those associated with the paintings of the first five rooms of Milan’s Museo del 900.

Many real phenomena may be modelled as random closed sets in ℝd, of different Hausdorff dimensions. The problem of the estimation of pointwise mean densities of absolutely continuous, and spatially inhomogeneous, random sets with Hausdorff dimension n < d, has been the subject of extended mathematical analysis by the authors. In particular, two different kinds of estimators have been recently proposed, the first one is based on the notion of Minkowski content, the second one is a kernel-type estimator generalizing the well-known kernel density estimator for random variables. The specific aim of the present paper is to validate the theoretical results on statistical properties of those estimators by numerical experiments. We provide a set of simulations which illustrates their valuable properties via typical examples of lower dimensional random sets.

Computer simulation of simultaneous evolution of individual texture components during recrystallization of an IF steel is carried out. A new methodology has been developed that takes as its starting point experimental data of each texture component evolving during recrystallization. In particular, Magnusson et al. data on IF steel was analyzed in a previous work with the help of the exact analytical tools developed by Rios and Villa for simultaneous transformations. From this analysis parameters such as number of nuclei of each texture component per unit of volume could be obtained and were employed as input for the present computer simulation. From this input 3-d microstructures could then be generated. The methodology proposed here combines experimental data, exact analytical methods and computer simulation and may be employed to extract the maximum information from the experimental data.

Heterogeneous transformations (or reactions) may be defined as those transformations in which there is a sharp moving boundary between the transformed and untransformed region. In Materials Science such transformations are normally called nucleation and growth transformations, whereas birth-and-growth processes is the preferred denomination in Mathematics. Recently, the present authors in a series of papers have derived new analytical expressions for nucleation and growth transformations with the help of stochastic geometry methods. Those papers focused mainly on the role of nuclei location in space, described by point processes, on transformation kinetics. In this work we focus on the effect that a random velocity of the moving boundaries of the grains has in the overall kinetics. One example of a practical situation in which such a model may be useful is that of recrystallization. Juul Jensen and Godiksen reviewed recent 3-d experimental results on recrystallization kinetics and concluded that there is compelling evidence that every grain has its own distinct growth rate. Motivated by this practical application we present here new general kinetics expressions for various situations of practical interest, in which a random distribution of growth velocities is assumed. In order to do this, we make use of tools from Stochastic Geometry and Geometric Measure Theory. Previously known results follow here as particular cases. Although the motivation for this paper was recrystallization the expressions derived here may be applied to nucleation and growth reactions in general.

Birth and growth processes are known in materials science as nucleation and growth processes. In crystalline materials nucleation almost always takes place in an internal crystalline defect. These defects are classified according to their dimensionality: point, line or planar defects. Therefore, investigating nucleation on sets of dimensionality lower than the set in which the transformation takes place is of paramount importance. Cahn (1956) in a classical work derived expressions for transformation kinetics when nucleation took place on random planes and on random straight lines. He used these expressions to describe nucleation in polycrystalline materials. He considered that nucleation on grain faces could be treated as nucleation on random planes and, likewise, nucleation on grain edges could be treated as nucleation on random lines. The present work revisits and generalizes Cahn’s treatment of nucleation on planes and lines. First a general expression for the case of nucleation on lower dimensional sets is obtained. After that general expressions for nucleation on random planes and random lines are given. This paper provides the mathematical basis for the development of more specific expressions to be used in practical applications. Although this work has been done bearing applications to materials science in mind the results obtained here may be applied to birth and growth processes in any field of science.

The problem of the evaluation of the so-called specific area of a random closed set, in connection with its mean boundary measure, is mentioned in the classical book by Matheron on random closed sets (Matheron, 1975, p. 50); it is still an open problem, in general. We offer here an overview of some recent results concerning the existence of the specific area of inhomogeneous Boolean models, unifying results from geometric measure theory and from stochastic geometry. A discussion of possible applications to image analysis concerning the estimation of the mean surface density of random closed sets, and, in particular, to material science concerning birth-and-growth processes, is also provided.

The scope of this paper is to offer an overview of the main results obtained by the authors in recent literature in connection with the introduction of a Delta formalism, á la Dirac-Schwartz, for random generalized functions (distributions) associated with random closed sets, having an integer Hausdorff dimension n lower than the full dimension d of the environment space Rd. A concept of absolute continuity of random closed sets arises in a natural way in terms of the absolute continuity of suitable mean content measures, with respect to the usual Lebesgue measure on Rd. Correspondingly mean geometric densities are introduced with respect to the usual Lebesgue measure; approximating sequences are provided, that are of interest for the estimation of mean geometric densities of lower dimensional random sets such as fbre processes, surface processes, etc. Many models in material science and in biomedicine include time evolution of random closed sets, describing birthand-growth processes; the Delta formalism provides a natural framework for deriving evolution equations for mean densities at all (integer) Hausdorff dimensions, in terms of the relevant kinetic parameters.

Microstructural evolution in three dimensions of nucleation and growth transformations is simulated by means of cellular automata (CA). In the simulation, nuclei are located in space according to a heterogeneous Poisson point processes. The simulation is compared with exact analytical solution recently obtained by Rios and Villa supposing that the intensity is a harmonic function of the spatial coordinate. The simulated data gives very good agreement with the analytical solution provided that the correct shape factor for the growing CA grains is used. This good agreement is auspicious because the analytical expressions were derived and thus are exact only if the shape of the growing regions is spherical.

Applying heat treatments using an autoclave and hot air sterilization can alter the proximal composition, technofunctional properties, and antinutrient content of Sacha inchi (P. volubilis) oil press cake. The autoclave and hot air treatments significantly reduced antinutrients compared to the control. The samples treated with autoclave and hot air sterilization exhibited a significant decrease in alkaloids, nitrates, tannins, saponins, and trypsin inhibitors compared to the control sample. However, the 20-min autoclave treatment did not significantly reduce the saponin antinutrients. Phytic acid significantly decreased in the 30-min hot air sample and autoclave 20-min/hot air treatments, respectively. On the other hand, the levels of antinutrients oxalate and thiocyanates did not significant difference between the control and hot air treatments. However, the autoclave treatment resulted in a significant reduction in oxalates. The study found that hydrotreatments at temperatures of 121 °C with humid heat - autoclave showed significant differences in protein content compared to the control sample, with content of 37.75 + 0.2 g/100g. Samples treated with an autoclave for 10, 20, and 30 min showed values of protein 53.19 + 0.28, 66.08 + 2.6, and 70.12 + 0.48 g/100g, respectively. Meanwhile, samples treated with dry heat showed significant differences with the sample treated for 10 min having a protein content of 60.21 + 6.80 g/100g. The techno-functional properties analyzed in the study demonstrated a significant decrease in hydrating properties such as water holding capacity (WHC), water retention capacity (WRC), and swelling capacity (SC) due to changes in the solubility of proteins for the two treatments and the oil holding capacity (OHC) property showed a significant increase. Finally, water's presence during hydrothermal treatments significantly reduces antinutrients, providing guidance for analyzing other study variables.

The article presents a profile of Santa Laura Montoya, a Colombian saint who dedicated her life to missions with indigenous people. Laura Montoya defied the difficult topography of her country to work in the jungles and remote villages of Colombia, with the aim of making indigenous people see themselves as children of God. She founded the community Missionaries of Mary Immaculate and Saint Catherine of Siena, known as Las Lauritas, which currently has 580 sisters worldwide. Laura Montoya had a painful childhood and a youth in search of her vocation, but she eventually became a teacher and joined the educational project for women at La Inmaculada school in Medellín. Despite facing difficulties and slander, Laura dedicated herself to teaching her students about religious life and Christian marriage. After a personal experience, Laura felt the vocation to mission with indigenous and minority ethnic groups. With the support of the president of Colombia and Monsignor Crespo, Laura began her missionary work in Dabeiba, a municipality with a significant presence of the Embera Chamí community. The text narrates the story of Laura Montoya, who, along with four women and her father, embarked on a journey to Dabeiba in 1914 to establish a religious community called Missionaries of Mary Immaculate and Saint Catherine of Siena. Despite facing opposition, they managed to found the community and began to expand through missions and permanent houses in different places. Laura was concerned with transmitting faith and advocated for laws to protect indigenous people and respect their culture. Despite criticism, her work was recognized and approved by the Holy See. The article talks about the life and legacy of Santa Laura Montoya, the only Colombian saint to date. Laura Montoya was a missionary who worked with indigenous people in Colombia, bringing hope and God's love through her work. Despite facing opposition and accusations, Laura Montoya managed to found a religious congregation and left a spiritual legacy through her writings and works. She was recognized for her work and received the Cross of Boyacá, the highest distinction from the Colombian government. Currently, her convent in Medellín is a place of pilgrimage where her remains and belongings can be visited. [Extracted from the article]