Salta, Argentina

Catholic University of Salta
Salta, Argentina
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Moya J.A.,Catholic University of Salta | Coisson M.,INRIM - Istituto Nazionale di Ricerca Metrologica
Journal of Materials Science | Year: 2017

A method for calculating saturation magnetostriction values in solid-solution ternary alloys is proposed using the magnetostriction data of binary alloys implicated in the ternary system and few data of ternary alloy. Studies on three systems are presented: the Fe–Al–Si system where a considerable magnetostriction data available in the literature was employed to perform the method; the Fe–Al–Ge system in which our data are compared and discussed with a previous study in this system; and the Fe–Ge–Si system for which iso-magnetostriction curves are proposed since only one experimental value in the literature was found. The results obtained by this method approximate previously reported experimental data. This can be used to design alloys with a defined value of magnetostriction reducing the number of samples and measurements or in calculations on theoretical models. In this sense, a hypothetical behaviour of magnetostriction in the Fe–Ge binary system for Ge > 20 at.%. is also presented. © 2017 Springer Science+Business Media, LLC

Moya J.A.,Catholic University of Salta
Review of Scientific Instruments | Year: 2016

A method and its system to study the structural evolution on soft magnetic amorphous and nanocrystalline ribbon shaped alloys are presented. With only one sample, a complete set of magnetic and electric data at room and at high temperature are obtained in a relatively short period of time, allowing us to elucidate the structural changes occurring in the alloy and to determine the optimal soft magnetic properties annealing conditions. © 2016 Author(s).

Moya J.A.,Catholic University of Salta
Journal of Magnetism and Magnetic Materials | Year: 2017

A new type of study is presented for magnetic and structural characterization of amorphous or nanocrystalline metallic alloys in ribbon or wire-shaped samples. A single sample is subjecting to successive steps of flash isocurrent heat treatments with increasing duration in time, followed by a rapid cooling, while magneto-electric properties evolution are scanned in situ at room temperature. When one set of isocurrent heat treatments is finished, the annealing current is increased and a new set of isocurrent treatments starts. The properties studied were the saturation magnetization and the coercive field at 50 Hz, magnetic permeability at 100 kHz and electrical resistance from where we also obtained the crystalline fraction. The method was applied on two samples of Finemet-like alloys and the results were analyzed from the perspective of current literature. With the present method it is possible to obtain a general and meticulous understanding of the structural and magnetic evolution of the samples tested, with a considerable saving of time and samples. © 2017 Elsevier B.V.

Quintana M.V.,National University of Salta | Quintana M.V.,Catholic University of Salta | Nallim L.G.,National University of Salta
International Journal of Mechanical Sciences | Year: 2013

A general variational formulation for the determination of natural frequencies and mode shapes of free vibration of symmetric laminated plates of trapezoidal and triangular shapes is presented in this work. The kinematics corresponding to the first-order shear deformation plate theory (FSDT) is used to take into account the effects of shear deformation and rotational inertia in the analysis. The developed approach is based on the Ritz method and the plate geometry is approximated by non-orthogonal right triangular co-ordinates. The transverse deflection and two rotations of the laminate are independently approximated by sets of simple polynomials. The algorithm allows obtaining approximate analytical solutions for laminated plates with different shapes, aspect ratio, number of layers, stacking sequence, angle of fiber orientation and boundary conditions including translational and rotational elastically restrained edges. The algorithm is simple to program and numerically stable. © 2013 Elsevier Ltd.

Moya J.A.,Catholic University of Salta | Gamarra Caramella S.,Catholic University of Salta | Marta L.J.,Catholic University of Salta | Berejnoi C.,National University of Salta
IEEE Transactions on Magnetics | Year: 2013

Magnetic properties of some nanocrystalline soft magnetic alloys are evaluated by means of a model obtained from literature. The influence of alloy elements in grain diameter, crystalline fraction and anisotropies are investigated in order to obtain information for the design of nanocrystalline soft magnetic materials. The study concerns materials with nanocrystalline composition of Fe, Fe-Si, Fe-Si-Al, and Fe-Ge, and is complemented with alloys containing nanocrystals of Fe and Fe-Co from literature. Results indicate that the reduction of grain diameter in Fe-based nanocrystal alloys is the main challenge to enhance the soft magnetic properties, when induced anisotropies are suppressed. For Fe-(Si,Al,Ge)-based nanocrystals, it is necessary to obtain a good balance of the magnetoelastic anisotropies. This can be achieved by modifying the amount of crystallized fraction via changes in the chemical composition of the nanocrystals and/or the matrix. In the case of Fe-Co, magnetic softness is attained by decreasing the Co content or with the addition of elements like Si or Al. © 1965-2012 IEEE.

Aller J.F.,Instituto Nacional de Tecnologia Agropecuaria | Cancino A.K.,Instituto Nacional de Tecnologia Agropecuaria | Rebuffi G.E.,Catholic University of Salta | Alberio R.H.,Instituto Nacional de Tecnologia Agropecuaria
Animal Reproduction Science | Year: 2010

Two experiments were conducted to determine the effect of estradiol benzoate (EB) and intravaginal progestagen treatment on ovarian follicular dynamics and superstimulatory response in eCG-treated llamas. The purpose of Experiment 1 was to evaluate the effect of EB and progestagen treatment starting at different phases of dominant follicle (DF1) development on regression pattern and subsequent follicle wave emergence (WE2) in lactating and non-lactating llamas. Early lactating (n = 24, 30 ± 4 days postpartum) and non-lactating (n = 24) females were assigned in equal numbers (n = 8) to one of three groups according to the phase of DF1 (growing, static or regressing) determined by ultrasonography from day -3 to day 0. At day 0, llamas received an intravaginal sponge (MPA, 150 mg) and 5 mg of MPA (i.m.). Half of the females (n = 4) of each group were injected with 2 mg (i.m.) of EB and half were not (control group). A 2 × 2 × 3 (lactational status, EB treatment and follicular phases) factorial design was used. Each sponge was removed 8 days later. Ovaries were monitored from day 0 to day 12. Daily blood samples were taken to determine 17β-estradiol (E2) profiles from day 0 to day 8. The DF1 regression pattern was not affected (P > 0.05) by the phase of follicle wave at the start of the treatment or any interactions among main effects. Follicle wave emergence in EB-treated llamas was delayed (P < 0.05) by 2.3 days compared with non-treated llamas. Following EB treatment, plasma concentrations of E2 were greater (P < 0.05) from day 1 to day 5 in the treated than in non-treated females, but not from day 6 onward (P > 0.05). Experiment 2 was designed to evaluate the effect of this treatment on the ovarian superovulatory response and embryo yield following eCG treatment administered on day of follicular wave emergence as determined in the Experiment 1. The same lactating (n = 18, 61 ± 4 days postpartum) and non-lactating (n = 18) llamas at random stages of follicle wave were treated as those in Experiment 1 and received 1200 IU of eCG at the time of WE2 (EB-treated = day 6.5 and non-treated = day 4.5). Llamas were mated 5 days after sponge withdrawal. A second mating was allowed 24 h later. Embryos were collected between 7 and 8 days after the first mating and blood samples were taken to determine progesterone (P4) concentrations. The mean number of follicles on day of mating and the number of CL on day of embryo collection were not affected by lactational status, EB treatment or their interactions (P > 0.05). Ovulation rate and mean (±SEM) number of recovered embryos for EB treatment group (67.5% and 2.4 ± 0.4) were greater (P < 0.05) than for no EB treatment (51.1% and 1.1 ± 0.4). Plasma P4 concentrations and number of CL per llama were correlated (r = 0.49; P = 0.014). In conclusion, progestagen plus EB treatment facilitates the prediction of the emergence of a new follicular wave approximately 6 days after treatment and resulted in a higher ovulation rate and embryo production in ovarian superstimulated llamas regardless of lactational status. © 2010 Elsevier B.V. All rights reserved.

Grau J.B.,Technical University of Madrid | Anton J.M.,Technical University of Madrid | Tarquis A.M.,Technical University of Madrid | Colombo F.,Catholic University of Salta | And 2 more authors.
Biogeosciences | Year: 2010

Multi-criteria Decision Analysis (MCDA) is concerned with identifying the values, uncertainties and other issues relevant in a given decision, its rationality, and the resulting optimal decision. These decisions are difficult because the complexity of the system or because of determining the optimal situation or behaviour. This work will illustrate how MCDA is applied in practice to a complex problem to resolve such us soil erosion and degradation. Desertification is a global problem and recently it has been studied in several forums as ONU that literally says: "Desertification has a very high incidence in the environmental and food security, socioeconomic stability and world sustained development". Desertification is the soil quality loss and one of FAO's most important preoccupations as hunger in the world is increasing. Multiple factors are involved of diverse nature related to: natural phenomena (water and wind erosion), human activities linked to soil and water management, and others not related to the former. In the whole world this problem exists, but its effects and solutions are different. It is necessary to take into account economical, environmental, cultural and sociological criteria. A multi-criteria model to select among different alternatives to prepare an integral plan to ameliorate or/and solve this problem in each area has been elaborated taking in account eight criteria and five alternatives. Six sub zones have been established following previous studies and in each one the initial matrix and weights have been defined to apply on different criteria. Three multicriteria decision methods have been used for the different sub zones: ELECTRE, PROMETHEE and AHP. The results show a high level of consistency among the three different multicriteria methods despite the complexity of the system studied. The methods are fully described for La Estrella sub zone, indicating election of weights, Initial Matrixes, algorithms used for PROMETHEE, and the Graph of Expert Choice showing the AHP results. A brief schema of the actions recommended for each of the six different sub zones is discussed. © Author(s) 2010.

Alicia Perez M.,Catholic University of Salta | Carolina Cardoso A.,Catholic University of Salta
Inteligencia Artificial | Year: 2014

Text mining has significant potential, as a substantial amount of the information available in organizations is in the form of unstructured text documents. One of the basic tasks in text mining is named-entity recognition (NER). This paper describes some of the main approaches to this task and applies them to a specific problem, namely information extraction from an 8000-document corpus of university administrative decisions. The experiments compare various approaches y show that conditional random fields (CRFs) are the best technique for the problem. The paper also describes the framework of this task, the unstructured information management architecture of which it is a component. © IBERAMIA and the authors.

Ceruti M.C.,Catholic University of Salta
BioMed Research International | Year: 2015

This study will focus on frozen mummies of sacrificial victims from mounts Llullaillaco (6739 m), Quehuar (6130 m), El Toro (6160 m), and the Aconcagua massif. These finds provide bioarchaeological data from mountaintop sites that has been recovered in scientifically controlled excavations in the northwest of Argentina, which was once part of the southern province of the Inca Empire. Numerous interdisciplinary studies have been conducted on the Llullaillaco mummies, including radiological evaluations by conventional X-rays and CT scans, which provided information about condition and pathology of the bones and internal organ, as well as dental studies oriented to the estimation of the ages of the three children at the time of death. Ancient DNA studies and hair analysis were also performed in cooperation with the George Mason University, the University of Bradford, and the Laboratory of Biological Anthropology at the University of Copenhagen. Ethnohistorical sources reveal interesting aspects related to the commemorative, expiatory, propitiatory, and dedicatory aspects of human sacrifice performed under Inca rule. The selection of the victims along with the procedures followed during the performance of the capacocha ceremony will be discussed, based on the bioarchaeological evidences from frozen mummies and the accounts recorded by the Spanish chroniclers. © 2015 Maria Constanza Ceruti.

Moya J.A.,Catholic University of Salta
Journal of Alloys and Compounds | Year: 2015

An approach to improve the soft magnetic properties of nanocomposite FINEMET-like alloys is presented by the study of the theoretical behavior of the coercive field with the crystallized fraction, Hc(νcr), curves where the total anisotropy is taken into account. These curves can exhibit a minimum value that should be used for a proper design of soft magnetic alloys, consisting in matching that value with the optimal crystallized fraction of the alloy. For this, the effect of Si, Ge, Co and Al on the magnetic properties on the material phases and on its microstructure was analyzed while a good relationship between theoretical results and data in the literature was found. Small amounts of Ge and/or Al can improve the magnetic properties of FINEMET while the addition of Co deteriorates the coercive field as is predicted by the theory. Simultaneous addition of two or more solute elements to the α-Fe crystals was also evaluated and discussed. Results indicate the importance of knowing the effect of the alloying element on the crystalline magnetostriction constant and on the crystallized fraction of the microstructure. © 2014 Elsevier B.V.

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