FRBA - Artículos en Revistas
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Item Una mirada en torno a la idea de autonomía en la Universidad Argentina(2015-06-12) Ramallo, MilenaEl presente trabajo parte de la tensión entre autonomía y responsabilidad social de la universidad. Luego se presenta un recorrido histórico-contextual y otro jurídico de la temática. El objetivo de este trabajo es vincular la concepción de la Responsabilidad Social propuesta por C. Cullen (2012) a partir de la noción de vulnerabilidad de Lévinas y las reflexiones que como respuesta a la introducción de la RSU se han llevado a cabo en torno a una de las características fundamentales: la autonomía de la universidad latinoamericana y argentina. Finalmente, se dejan abiertas importantes preguntas en sus conclusiones.Item La evaluación de la Responsabilidad Social Universitaria(2015-07-02) Ramallo, MilenaEn la construcción del concepto de Responsabilidad Social Universitaria (RSU) y su evaluación en especial en el nivel universitario, podemos encontrar distintas formas de comprenderlo dado el múltiple marco referencial existente sobre el tema. Sin embargo, estas nociones aún han sido poco estudiadas y desarrolladas por grupos de investigadores en universidades o centros de estudio, y menos aún resignificadas distinguiéndolas del sentido que poseen en el ámbito empresarial. Varios estudios plantean la necesidad de proponer criterios que permitan determinar si una facultad o universidad actúa con responsabilidad social: el tema de su evaluación. El análisis realizado en el presente trabajo muestra la relación existente entre las concepciones de RSU y las concepciones de su evaluación.Item El desarrollo sostenible (DS) en la formación de ingenieros: un nuevo campo para repensar la perspectiva CTS(2017-05-01) Ramallo, Milena; Cardaci, Karina Florencia; Costucica, Leonardo Adán DouglasEste trabajo parte del supuesto que la incorporación de la enseñanza de la ingeniería en el ámbito universitario es una novedad del siglo XX y está vinculada al modelo productivo del segundo ciclo de acumulación del capital. Ese modo de producción industrial se nutre de aquella cosmovisión, aún dominante aunque haya entrado en crisis. En este contexto, el Desarrollo Sostenible (DS) se propone como uno de los aspectos del campo actual de la Ciencia, Tecnología y Sociedad (CTS). El objetivo de este trabajo es reflexionar acerca de los posibles cambios que esta nueva visión aporte a la formación de los ingenieros. Para ello, se propone el análisis de los cambios en la concepción de la ingeniería y en especial qué genera el nuevo paradigma, a nivel nacional, regional e internacional. Por último, se concluye sobre el desafío de la ingeniería para contribuir con el DS.Item Ingeniería y Sociedad: aportes de los estudios CTS en la formación de los ingenieros(2019-06-28) Ramallo, Milena; Repetto, Élida; Gayoso, María Celia; Giacomino, RosaEl objetivo de este trabajo es presentar los aportes del enfoque CTS e incorporarlos a la asignatura "Ingeniería y sociedad" en las carreras de ingeniería de la Universidad Tecnológica Nacional de Argentina. Esta fundamentación brinda elementos teóricos y metodológicos para la reflexión sobre la pertinencia de este campo de estudio-trabajo en la formación de ingenieros. Su objeto de estudio se centra en la relación entre la ciencia y la tecnología, hoy en día atravesada por una nueva concepción de la ingeniería atenta a las necesidades de una sociedad que anhela alcanzar el desarrollo sustentable. Esto ha impuesto un nuevo desafío a la ciencia y la tecnología, y este nuevo modelo a su vez se relaciona profundamente con la nueva manera de comprender la relación ciencia-tecnología-ingeniería-industria en un mundo complejo y cambiante. Por ello nos proponemos desarrollar en los estudiantes la capacidad de comprensión de ese mundo que les toca vivir y de los desafíos que tendrá que afrontar el ingeniero, así como también entender el valor social de la ingeniería.Item Photocatalytic activity of TiO2 films prepared by cathodic arc deposition: dependence on thickness and reuse of the photocatalysts(2020-01-25) Meichtry, Jorge Martín; Vega, Daniel; Kleiman, Ariel; Litter, Marta Irene; Márquez, AdrianaIn this work, the photocatalytic activity of anatase films with thicknesses up to 1100 nm prepared by cathodic arc deposition (CAD) on glass substrates is reported. The photocatalytic activity under UV?Vis irradiation (λ > 330 nm) was evaluated through the efficiency in the reduction of 0.80 mM Cr(VI) in the presence of 1 mM ethylenediaminetetraacetic acid (EDTA) at pH 2, and compared with the performance of samples obtained by dip-coating using commercial P25. The CAD films were optically transparent, with visible light transmittance ≥ 50% even for the thickest samples. The photocatalytic efficiency of the films increased as the thickness increased. The possibility of obtaining thicker films allowed cathodic arc films reaching better performance than P25 samples. For the most active films obtained by CAD, complete Cr(VI) reduction could be obtained in <300 min under a 28 W m−2 UV-A irradiance. The photocatalytic reaction for all the studied TiO2 films obeyed pseudo-first order kinetics. A decrease of the reaction rate constant was observed for both types of films after reusing the photocatalysts. The fate of the reduced Cr(VI) was also analyzed.Item Evaluation of the bias in the management of patient’s appointments in a pediatric office(2020-04-01) Vegega, Cinthia; Pytel, Pablo; Pollo Cattaneo, María FlorenciaThe application of Machine Learning algorithms must always take into account the objectives set within the project, the characteristics of the domain where the project will be carried out and the data available to use. Given this, it is essential before collecting data considered as representative of the problem to be solved, because otherwise there may be hidden biases in the data and these may solve a different problem from the one intended. In this context, the aim of this work is to apply a process based on the Gridding method that allows the analysis of the features of the data to be used. This process is applied to the historical data of a pediatric medical office where it is sought to implement an intelligent system that allows to predict the number of normal and overshift appointments for a particular date and time, since it is desired to hire, when necessary, another pediatric doctor to assist in the care of patients.Item Effect of different gases on the sonochemical Cr(VI) reduction in the presence of citric acid(2020-12-01) Meichtry, Jorge Martín; Cancelada, Lucía; Destaillats, Hugo; Litter, Marta IreneThe sonochemical (850 kHz) Cr(VI) reduction (0.30 mM, pH 2) in the presence of citric acid (Cit, 2 mM) was analyzed under different working atmospheres: reactor open to air without sparging (ROAWS), and Ar, O2, air and N2 sparging. Hydrogen peroxide formation in pure water at pH 2 and KI dosimetry were also measured. Zero-order kinetics was observed in all cases. A complete Cr(VI) reduction after 180 min insonation was obtained with the ROAWS and under Ar, while a lower Cr(VI) reduction efficiency was achieved under the other conditions. The Cr(VI) reduction and H2O2 formation rates followed the order ROAWS ?° Ar > air ?° O2 >> N2, while for KI dosimetry the order was ROAWS >> O2 ?° air > Ar >> N2. This indicates that H2O2 formation rate is a better measure of the system reactivity for Cr(VI) reduction. For air, O2 and N2, once the sparging was stopped, Cr(VI) reduction rate increased up to approximately the same value obtained for the ROAWS, suggesting that the sparging decreased the generation of reactive species and, thus, the Cr(VI) reduction rate. Nitrate production was measured at low concentrations (micromolar range) in the ROAWS, air and N2 systems. Formic and acetic acids were detected as Cit degradation products. Reaction mechanisms were proposed. It can be concluded that the best conditions for Cr(VI) removal are with the ROAWS because of a higher Cr(VI) reduction rate, no atmosphere control is required, and it is a less expensive system.Item Smart Fibrous Structures Produced by Electrospinning Using theCombined Effect of PCL/Graphene Nanoplatelets(2021-01-26) Francavilla, Paola; Ferreira, Diana; Araujo, Joana; Fangueiro, RaulOver the years, the development of adaptable monitoring systems to be integrated into soldiers’ body gear, making them as comfortable and lightweight as possible (avoiding the use of rigid electronics), has become essential. Electrospun microfibers are a great material for this application due to their excellent properties, especially their flexibility and lightness. Their functionalization with graphene nanoplatelets (GNPs) makes them a fantastic alternative for the development of innovative conductive materials. In this work, electrospun membranes based on polycaprolactone (PCL) were impregnated with different GNPs concentrations in order to create an electrically conductive surface with piezoresistive behavior. All the samples were properly characterized, demonstrating the homogeneous distribution and the GNPs’ adsorption onto the membrane’s surfaces. Additionally, the electrical performance of the developed systems was studied, including the electrical conductivity, piezoresistive behavior, and Gauge Factor (GF). A maximum electrical conductivity value of 0.079 S/m was obtained for the 2%GNPs-PCL sample. The developed piezoresistive sensor showed high sensitivity to external pressures and excellent durability to repetitive pressing. The best value of GF (3.20) was obtained for the membranes with 0.5% of GNPs. Hence, this work presents the development of a flexible piezoresistive sensor, based on electrospun PCL microfibers and GNPs, utilizing simple methods.Item Minimization of the Line Resistance Impact on Memdiode-Based Simulations of Multilayer Perceptron Arrays Applied to Pattern Recognition(2021-02-21) Palumbo, FelixIn this paper, we extend the application of the Quasi-Static Memdiode model to the realistic SPICE simulation of memristor-based single (SLPs) and multilayer perceptrons (MLPs) intended for large dataset pattern recognition. By considering ex-situ training and the classification of the hand-written characters of the MNIST database, we evaluate the degradation of the inference accuracy due to the interconnection resistances for MLPs involving up to three hidden neural layers. Two approaches to reduce the impact of the line resistance are considered and implemented in our simulations, they are the inclusion of an iterative calibration algorithm and the partitioning of the synaptic layers into smaller blocks. The obtained results indicate that MLPs are more sensitive to the line resistance effect than SLPs and that partitioning is the most effective way to minimize the impact of high line resistance valuesItem Temperature of Conductive Nanofilaments in Hexagonal Boron Nitride Based Memristors Showing Threshold Resistive Switching(2021-04-11) Palumbo, FelixTwo-terminal metal/insulator/metal (MIM) memristors exhibiting threshold resistive switching (RS) can develop advanced key tasks in solid-state nano/ micro-electronic circuits, such as selectors and integrate-and-fire electronic neurons. MIM-like memristors using multilayer hexagonal boron nitride (h-BN) as dielectric are especially interesting because they have shown threshold RS with ultra-low energy consumption per state transition down to the zeptojoule regime. However, the factors enabling stable threshold RS at such low operation energies are still not fully understood. Here it is shown that the threshold RS in 150 nm × 150 nm Au/Ag/h-BN/Au memristors is especially stable because the temperature in the h-BN stack during operation (i.e., at low currents ≈1 μA) is very low (i.e., ≈310 K), due to the high in-plane thermal conductivity of h-BN and its low thickness. Only when the device is operated at higher currents (i.e., ≈200 μA) the temperatures at the h-BN increase remarkably (i.e., >500 K), which produce a stable non-volatile conductive nanofilament (CNF). This work can bring new insights to understand the performance of 2D materials based RS devices, and help to develop the integration of 2D materials in high-density nanoelectronicsItem Treatment of ethylmercury chloride by heterogeneous photocatalysis over TiO2(2021-04-15) de la Fourniere, Emmanuel; Meichtry, Jorge Martín; Gautier, Eduardo Amilcar; Leyva, Ana Gabriela; Litter, Marta IreneEthylmercury chloride (C2H5HgCl) was treated by UV/TiO2 photocatalysis in the presence of O2 and under N2 at pH 4.2. No report exists on C2H5Hg+ degradation by heterogeneous photocatalysis. The adsorption of C2H5Hg+ over TiO2 (no irradiation) was studied and fitted to the Freundlich isotherm. The photocatalytic evolution of C2H5Hg+ was adjusted to a two parameter Langmuir-Hinshelwood model, modified to include a third parameter attributed to the deactivation caused by the deposition of Hg(0). Hg(II) in solution, Hg(0) and Hg2Cl2 (detected only under N2) were the products of the photocatalytic degradation; the organic moiety was degraded but no organic by-product could be detected. Experiments in the absence of O2 showed a higher conversion rate, indicating that C2H5Hg+ is removed both by oxidative and reductive pathways, being this last step partially inhibited by O2. A degradation mechanism considering both oxidative and reductive one-electron transfer steps is proposed.Item On the Thermal Models for Resistive Random Access Memory Circuit Simulation(2021-05-11) Palumbo, FelixResistive Random Access Memories (RRAMs) are based on resistive switching (RS) operation and exhibit a set of technological features that make them ideal candidates for applications related to non-volatile memories, neuromorphic computing and hardware cryptography. For the full industrial development of these devices different simulation tools and compact models are needed in order to allow computer-aided design, both at the device and circuit levels. Most of the different RRAM models presented so far in the literature deal with temperature effects since the physical mechanisms behind RS are thermally activated; therefore, an exhaustive description of these effects is essential. As far as we know, no revision papers on thermal models have been published yet; and that is why we deal with this issue here. Using the heat equation as the starting point, we describe the details of its numerical solution for a conventional RRAM structure and, later on, present models of different complexity to integrate thermal effects in complete compact models that account for the kinetics of the chemical reactions behind resistive switching and the current calculation. In particular, we have accounted for different conductive filament geometries, operation regimes, filament lateral heat losses, the use of several temperatures to characterize each conductive filament, among other issues. A 3D numerical solution of the heat equation within a complete RRAM simulator was also taken into account. A general memristor model is also formulated accounting for temperature as one of the state variables to describe electron device operation. In addition, to widen the view from different perspectives, we deal with a thermal model contextualized within the quantum point contact formalism. In this manner, the temperature can be accounted for the description of quantum effects in the RRAM charge transport mechanisms. Finally, the thermometry of conducting filaments and the corresponding models considering different dielectric materials are tackled in depth.Item Decoupling the sequence of dielectric breakdown in single device bilayer stacks by radiation-controlled, spatially localized creation of oxide defects(2021-06-14) Palumbo, FelixThe breakdown (BD) sequence in high-K/interfacial layer (HK/IL) stacks for timedependent dielectric breakdown (TDDB) has remained controversial for sub-45 nm CMOS nodes, as many attempts to decode it were not based on proper experimental methods. Knowhow of this sequence is critical to the future design for reliability of FinFETs and nanosheet transistors. We present here the use of radiation fluence as a tool to precisely tune the defect density in the dielectric layer, which jointly with the statistical study of the soft, progressive and hard BD, allow us to infer the BD sequence using a single HfO2-SiOx bilayered MOS structureItem New insights on the UV/TiO2 photocatalytic treatment of thiomersal and its 2-sulfobenzoic acid product(2021-06-28) de la Fourniere, Emmanuel; Meichtry, Jorge Martín; Gautier, Eduardo Amilcar; Custo, Graciela; Litter, Marta IreneAbstract: Background: Thiomersal (TM), a complex between 2-mercaptobenzoic acid (2-MBA) and ethylmercury (C2H5Hg+), is an antimicrobial preservative used in immunological, ophthalmic, cosmetic products, and vaccines. Objective: TM has been treated by UV/TiO2 photocatalysis in the presence or absence of oxygen at acidic pH. C2H5Hg+, 2-MBA, and 2-sulfobenzoic acid (2-SBA) were found as products. A 2-SBA photocatalytic treatment was undertaken to study sulfur evolution. Methods: Photocatalytic runs were performed using a UVA lamp (λmax = 352 nm), open to air or under N2. A suspension of the corresponding TM or 2-SBA salt and TiO2 was prepared, and pH was adjusted. Suspensions were stirred in the dark for 30 min and then irradiated. TM, 2-MBA, 2-SBA, and C2H5Hg+ were quantified by HPLC, sulfur by TXRF, and the deposits on the photocatalyst were analyzed by chemical reactions. The mineralization degree was followed by TOC. Sulfate was determined using BaCl2 at 580 nm. Results: Photocatalytic destruction of TM and total C2H5Hg+ was complete under N2 and air, but TM degradation was much faster in air. The evolution of TM and the products followed a pseudo-first order kinetics. Conclusion: TiO2-photocatalytic degradation is a suitable technique for the treatment of TM and its degradation products. In contrast to other organomercurial compounds, TM degradation is faster in the presence of O2, indicating that the oxidative mechanism is the preferred pathway. A significant TM mineralization (> 60%, NPOC and total S) was obtained. TM was more easily degraded than 2-SBA. Sulfate was the final productItem Classification and detection of honey adulteration through corona discharge-induced plasma spectroscopy and electronic plasma nose(2021-06-30) Ferrarra, Leonardo; Puntoriero, Luis; Boggio, Norberto; Vorobioff, Juan; Cáceres, Jorge; De Simone, Ricardo; Rinaldi, CarlosIn the past, a large group of syrups and markers of honey adulteration have been identified, but new syrups are now closely matching their composition, and detection of honey adulteration is becoming considerably more difficult. In this work, we present a methodology that allows us to characterize honey samples providing a solution to this problem using corona discharge-induced plasma spectroscopy (CDIPS) in conjunction with electronic plasma nose (eP-Nose). Applying chemometric analysis it was possible to distinguish the different types of honey and determine the degree of adulteration in them with corn syrup. To our knowledge, this is the first time that this technique has been applied to determine the fingerprint (authenticity) of honey samples of different origins. The elemental composition of honey provides enough information to get correct discrimination of different adulteration. The result of the chemometric analysis showed over 98% certainty and all honey samples were correctly identified. There have been no instances of false positives or false negatives in our tests or applications. This methodology shows high potential as an alternative method for monitoring and analyzing the quality and purity in honey production, especially for fraud detection.Item Standards for the Characterization of 2 Endurance in Resistive Switching Devices(2021-10-07) Palumbo, FelixResistive switching (RS) devices are emerging 11 electronic components that could have applications in multiple 12 types of integrated circuits, including electronic memories, true 13 random number generators, radiofrequency switches, neuro- 14 morphic vision sensors, and artificial neural networks. The 15 main factor hindering the massive employment of RS devices in 16 commercial circuits is related to variability and reliability issues, 17 which are usually evaluated through switching endurance tests. 18 However, we note that most studies that claimed high 19 endurances >106 cycles were based on resistance versus cycle 20 plots that contain very few data points (in many cases even 21 <20), and which are collected in only one device. We 22 recommend not to use such a characterization method because 23 it is highly inaccurate and unreliable (i.e., it cannot reliably demonstrate that the device effectively switches in every cycle and 24 it ignores cycle-to-cycle and device-to-device variability). This has created a blurry vision of the real performance of RS devices 25 and in many cases has exaggerated their potential. This article proposes and describes a method for the correct 26 characterization of switching endurance in RS devices; this method aims to construct endurance plots showing one data point 27 per cycle and resistive state and combine data from multiple devices. Adopting this recommended method should result in 28 more reliable literature in the field of RS technologies, which should accelerate their integration in commercial products.Item Resultados de la encuesta sobre necesidades de formación en el sector textil(2021-12) Lippi, Andrea; Marino, PatriciaEl procesamiento textil, (hilandería, tejedurías, tintorería y terminación y no tejidos), presenta una oferta muy baja en materia de entidades y acciones de capacitación hacia esos sectores, no existiendo formación orientada a técnicos que ocuparían cargos de nivel medio. Esta vacancia se produce en un sector que es gran empleador de mano de obra, con fuerte impacto en el PBI industrial, amplia distribución geográfica y un gran entramado de empresas pymes. En el marco del proyecto el BID-Fundación Protejer se detectó la necesidad de realizar un relevamiento, mediante una encuesta sectorial, de las necesidades formativas del sector productivo de manera de cerrar la brecha de habilidades en el sector. Así mismo entre las preguntas algunas de ellas estuvieron destinadas a evaluar el nivel de adaptación en las habilidades de los trabajadores a los cambios tecnológicos acelerados que se producen en la economía como resultado de la cuarta revolución industrial. Las conclusiones corresponden a las respuestas de 212 empresas de los distintos subsectores de la agro industria textil e indumentaria.Item ECG signals classification using overlapping variables to detect atrial fibrillation(2022-03-01) Ziccardi, I. G.; Rey, A. A.; Legnani, W. E.In the present work a method for the detection of the cardiac pathology known as atrial fibrillation is proposed by calculating different information, statistics and other nonlinear measures over ECG signals. The original database contains records corresponding to patients who are diagnosed with this disease as well as healthy subjects. To formulate the dataset the R´enyi permutation entropy, Fisher information measure, statistical complexity, Lyapunov exponent and fractal dimension were calculated, in order to determine how to combine this features to optimize the identification of the signals coming from ECG with the above mentioned cardiac pathology. With the aim to improve the results obtained in previous studies, a classification method based upon decision trees algorithms is implemented. Later a Montecarlo simulation of one thousand trials is performed with a seventy percent randomly selected from the dataset dedicated to train the classifier and the remaining thirty percent reserved to test in every trial. The quality of the classification is assessed through the computation of the area under the receiver operation characteristic curve (ROC), the F1-score and other classical performance metrics, such as the balanced accuracy, sensitivity, specificity, positive and negative predicted values. The results show that the incorporation of all these features to the dataset when are employed to train the classifier in the training task produces the best classification, in such a way that the largest quality parameter is achieved.Item An alternative computation of the entropy of 1D signals based on geometric properties(2022-09-01) Bonini, Cristian; Rey, Andrea; Otero, Dino; Amadio, Ariel; García Blesa, Manuel; Legnani, WalterThe objective of this work is to present a novel methodology based on the computation of a couple of geometric characteristics of the position of the data points in 1D signal to propose an alternative estimation of signal entropy. The conditions to be fulfilled by the signal are minimal; only those necessary to meet the sampling theorem requirement are enough. This work shows some examples in which the proposed methodology can distinguish among signals that cannot be differentiated by other in-use alternatives. Additionally an original example where the usual ordinal pattern algorithm to compute entropy is not applicable, is presented and analyzed. The proposal developed through this work carries some advantages over other alternatives and constitutes a true advancement in the pathway to compute the distribution function of the sequential points of 1D signals later used to compute the entropy of the signal.Item De la urgencia pandémica a nuevas alternativas de enseñanza(2022-10-07) Paruelo, JorgeEl período de pandemia obligó a los profesores a adoptar nuevas formas para llevar adelante las cursadas de las materias dentro de la universidad. Hubo que utilizar recursos tecnológicos para la enseñanza remota pensando en abarcar los casos de estudiantes con baja disponibilidad técnica y también buscando sostener la calidad de la enseñanza. Esto condujo a un entrenamiento de los profesores en nuevas tecnologías y nuevas estrategias de enseñanza. Este artículo toma la experiencia adquirida y la combina con un recurso didáctico recuperado de un curso de ingreso universitario de hace más de medio siglo junto con la metodología conocida como “aula invertida” para diseñar un tipo de curso que apunta a la participación activa del estudiante en su aprendizaje en el aula.