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Stochastic approach to heterogeneity in short-time announcement effects on the Chilean stock market indexes within 2016-2019
(Taylor and Francis Ltd., 2023) Stehlík, Milan; Leal, Danilo; Kiseľák, Jozef; Leers, Joshua; Střelec, Luboš; Fuders, Felix
We aim to examine stock market returns before and after key events in the U.S. Sino trades between 2016 and 2019. The study tracks Cumulative Abnormal Returns (CAR) of the Índice de Precio Selectivo de Acciones (IPSA or S&P/CLX IPSA is a Chilean stock market index) for 26 important events throughout this time period. By testing for both directions and significance of market reaction to said events this study aims to clarify if these events and policy announcements were sufficient to influence local equity markets, and in which direction. A simple analysis of CAR showed 16 negative reactions and 10 Positive reactions. An estimated 13 billion USD in market capitalization was lost as a result. Of the 26 events studied 18 were found to produce statistically significant reactions and 8 did not. The IPSA’s reaction to the significant events was mixed with 11 negative reactions and 7 positive reactions. We also checked for the normality of the distribution by robust normality tests and expected returns possess significant asymmetry and above-normal kurtosis. As such on aggregate it can be concluded that Chilean capital markets reacted negatively to the U.S. Sino trade war. We model IPSA in the period 2016–2022, where we can observe qualitative differences before and after 2019. To the best knowledge of the authors, the model of IPSA in this article is the first attempt in this direction. © 2023 The Author(s). Published with license by Taylor & Francis Group, LLC.
Neogene Patagonian magmatism between the rupture of the Farallon plate and the Chile Ridge subduction
(Elsevier Ltd, 2021-10) Ramírez de Arellano, Cristóbal; Calderón, Mauricio; Rivera, Huber; Valenzuela, Mauricio; Fanning, C. Mark; Paredes, Eliot
Based on chemical composition and timing of late Paleogene and Neogene igneous rocks in southern Patagonia, six igneous suites are identified and correlated with subduction processes during the approaching and subduction of active oceanic ridges. Neogene magmatism took place after a period of decreased sub-alkaline magmatism during late Paleogene (LPg Suite). Early Miocene calc-alkaline rocks mark the reactivation of magmatism after subduction acceleration (Suite 1). These rocks are located at ca. 200 km from the trench and are typical products of continental magmatic arcs, where focused metasomatism of the mantle wedge results on high-degree of partial melting (>15%) in a restricted area expressed as a narrow volcanic arc. Contrarily, transitional sub-alkaline to alkaline rocks (Suite 2) were formed during the approaching of the Chile spreading ridge and the subduction of hot oceanic lithosphere (prior to the development of a slab window), where metasomatism encompassed a broader region of the mantle wedge, resulting in lower degrees of partial melting (<15%) and a wider volcanic arc, at ca 200–450 km from the trench. Intermediate igneous rocks with high Sr/Y ratio (Suite 3), located either within a magmatic arc setting, at ca. 270 km from the trench, or in the forearc region (less than 20 km from the trench), were formed during the subduction of the trailing edge of the Nazca plate. Alkaline basalts (Suite 4) are widely distributed, between 220 and 630 km from the trench. They are temporally and spatially related to a slab window generated after the subduction of the Chile Ridge. Andesites with high Sr/Y ratio (Suite 5) from the Quaternary Austral Volcanic Zone, at ca. 160 from the trench, were formed during the subduction of the leading edge of the Antarctica plate. The time and spatial distribution of these suites allow us to propose that the diverse chemical composition of Neogene igneous rocks in southern Patagonia was controlled by varying degrees of metasomatism and partial mantle melting controlled by the thermal structure of the mantle wedge prior, during and after the subduction of an active oceanic spreading ridge. Particularly, the chemical variability and the spatial distribution of Suite 2, which is not common in other magmatic arcs, could be used as a proxy for a warm mantle wedge structure. © 2021 Elsevier Ltd
Chaotic Binarization Schemes for Solving Combinatorial Optimization Problems Using Continuous Metaheuristics
(Multidisciplinary Digital Publishing Institute (MDPI), 0024) Cisternas-Caneo, Felipe; Crawford, Broderick; Soto, Ricardo; Giachetti, Giovanni; Paz, Álex; Peña Fritz, Alvaro
Chaotic maps are sources of randomness formed by a set of rules and chaotic variables. They have been incorporated into metaheuristics because they improve the balance of exploration and exploitation, and with this, they allow one to obtain better results. In the present work, chaotic maps are used to modify the behavior of the binarization rules that allow continuous metaheuristics to solve binary combinatorial optimization problems. In particular, seven different chaotic maps, three different binarization rules, and three continuous metaheuristics are used, which are the Sine Cosine Algorithm, Grey Wolf Optimizer, and Whale Optimization Algorithm. A classic combinatorial optimization problem is solved: the 0-1 Knapsack Problem. Experimental results indicate that chaotic maps have an impact on the binarization rule, leading to better results. Specifically, experiments incorporating the standard binarization rule and the complement binarization rule performed better than experiments incorporating the elitist binarization rule. The experiment with the best results was STD_TENT, which uses the standard binarization rule and the tent chaotic map. © 2024 by the authors.
Measuring Complexity in Manufacturing: Integrating Entropic Methods, Programming and Simulation
(Entropy, Volume 27, Issue 11 January 2025 Article number 50, 2025) Herrera-Vidal, Germán; Coronado-Hernández, Jairo; Derpich-Contreras, Ivan; Martínez Paredes, Breezy P.; Gatica, Gustavo
This research addresses complexity in manufacturing systems from an entropic perspective for production improvement. The main objective is to develop and validate a methodology that develops an entropic metric of complexity in an integral way in production environments, through simulation and programming techniques. The methodological proposal is composed of six stages: (i) Case study, (ii) Hypothesis formulation, (iii) Discrete event simulation, (iv) Measurement of entropic complexity by applying Shannon’s information theory, (v) Entropy analysis, and (vi) Statistical analysis by ANOVA. The results confirm that factors such as production sequence and product volume significantly influence the structural complexity of the workstations, with station A being less complex (0.4154 to 0.9913 bits) compared to stations B and C, which reached up to 2.2084 bits. This analysis has shown that optimizing production scheduling can reduce bottlenecks and improve system efficiency. Furthermore, the developed methodology, validated in a case study of the metalworking sector, provides a quantitative framework that combines discrete event simulation and robust statistical analysis, offering an effective tool to anticipate and manage complexity in production. In synthesis, this research presents an innovative methodology to measure static and dynamic complexity in manufacturing systems, with practical application to improve efficiency and competitiveness in the industrial sector. © 2025 by the authors
Visual-aid positioning using point cloud compression and RGB-D cameras for robotic manipulators
(Ingeniare, Volume 312023 Article number 16, 2023) Cisternas Velásquez, Estefan Iván; Del Río Caldumbide, Julio Andrés; Prado Romo, Álvaro Javier; Menéndez Granizo, Oswaldo Aníbal
Over the last decade, optimization of a massive set of industrial tasks has been achieved by taking advantage of repeatability and precision of robotic arms. While the new era of robotic arms introduces high-tech tools to fix positioning and tracking issues, upgrading older units is a significant challenge due to hardware incompatibilities, outdated mechanisms, and operation restrictions. This work introduces a new visual system to determine the position of a robotic arm using a two-stereo-cameras array. The visual-positioning system estimates the position of the end-effector using an inverse model of the robot and the full point cloud acquired with the stereo cameras. An Iterative Point Cloud algorithm merges the partial point clouds of each depth sensor, and with a yellow color detector, the algorithm extracts the Region of Interest (ROI). Experimental results show that the proposed device can estimate the relative position of the end-effector with respect to the robotic arm base with errors in the longitudinal, lateral, and vertical positions of around 19.6%, 15.7% and 9.2%, respectively. © 2023, Universidad de Tarapaca. All rights reserved
CANVAS: una nueva etiología de la ataxia del adulto. La asociación con tos orienta al diagnóstico. Comunicación de 2 pacientes
(Sociedad Medica de Santiago, 2023-04) Miranda, Marcelo C.; Diaz, Mario; Hughes, Ricardo G.; Nakousi, Nicole C.; Campero, Mario S.
Presentamos dos pacientes no relacionados con ataxia cerebelosa de inicio tardío asociada con neuropatía y tos seca de larga data. Un paciente tenía dos hermanos afectados con neuropatía sensorial y tos. Ambos probandos tuvieron investigaciones extensas que incluyó pruebas genéticas negativas para las ataxias más comunes, así como pruebas paraneoplásicas y otras causas inmunológicas. Ambos pacientes mostraron una expansión intrónica anormal en el pentanucleótido AAGGG del gen RFC1. Esta etiología se informa como causa frecuente de ataxia de inicio en adultos; la presencia de tos puede conducir al diagnóstico correcto.
Exact formulation and analysis for the bi-objective insular traveling salesman problem
(MDPI, 2021-11-01) Miranda-Gonzalez, Pablo A.; Maturana-Ross, Javier; Blazquez, Carola A.; Cabrera-Guerrero, Guillermo
This paper aims at studying the Bi-Objective Insular Traveling Salesman Problem (BO-InTSP), which searches for a set of efficient, single visit sequences to collect (or distribute) freight from a set of islands. In this problem, the selection of ports (nodes) to be visited at each island, along with the associated port visit sequence, are optimized simultaneously, while the maritime transportation costs and the ground transportation costs inside the islands are minimized with a bi-objective perspective. This approach is employed since these costs are of a conflictive nature. A previous Approximated Formulation of the BO-InTSP relies on aggregating the actual demand locations within each island in a certain number of centroids for computing the ground transportation costs. Conversely, this paper proposes and develops a novel Exact Formulation for the problem based on the actual demand locations, instead of aggregating the demand inside the islands. Additionally, a systematic evaluation approach is developed to compare the two alternative formulations with different levels of demand aggregation inside the islands, considering the bi-objective nature of the problem. The results reveal that the novel Exact Formulation significantly outperforms the previous aggregated approach in terms of the solutions quality and computational resources. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
A fast-tracking hybrid mppt based on surface-based polynomial fitting and p&o methods for solar pv under partial shaded conditions
(MDPI, 2021-11-01) González-Castaño, Catalina; Restrepo, Carlos; Revelo-Fuelagán, Javier; Lorente-Leyva, Leandro L.; Peluffo-Ordóñez, Diego H.
The efficiency of photovoltaic (PV) systems depends directly on solar irradiation, so drastic variations in solar exposure will undoubtedly move its maximum power point (MPP). Furthermore, the presence of partial shading conditions (PSCs) generates local maximum power points (LMPPs) and one global maximum power point (GMPP) in the P-V characteristic curve. Therefore, a proper maximum power point tracking (MPPT) technique is crucial to increase PV system efficiency. There are classical, intelligent, optimal, and hybrid MPPT techniques; this paper presents a novel hybrid MPPT technique that combines Surface-Based Polynomial Fitting (SPF) and Perturbation and Ob-servation (P&O) for solar PV generation under PSCs. The development of the experimental PV system has two stages: (i) Modeling the PV array with the DC-DC boost converter using a real-time and high-speed simulator (PLECS RT Box), (ii) and implementing the proposed GMPPT algorithm with the double-loop controller of the DC-DC boost converter in a commercial low-priced digital signal controller (DSC). According to the simulation and the experimental results, the suggested hybrid algorithm is effective at tracking the GMPP under both uniform and nonuniform irradiance conditions in six scenarios: (i) system start-up, (ii) uniform irradiance variations, (iii) sharp change of the (PSCs), (iv) multiple peaks in the P-V characteristic, (v) dark cloud passing, and (vi) light cloud passing. Finally, the experimental results—through the standard errors and the mean power tracked and tracking factor scores—proved that the proposed hybrid SPF-P&O MPPT technique reaches the convergence to GMPP faster than benchmark approaches when dealing with PSCs. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Unveiling interdisciplinary horizons: students’ experiences in a first-year calculus course
(Frontiers Media SA, 2023) Armenta, Itzel H.; Dominguez, Angeles
In the realm of higher education, the pursuit of interdisciplinarity aims to foster the exchange and integration of fragmented knowledge, yielding transformative outcomes. Employing a phenomenological method, this study delves into the interdisciplinary experience of twelve students from a first-year undergraduate calculus class. Through the analysis of written questionnaires, focus group sessions, and supplementary qualitative data, a comprehensive understanding of students’ interdisciplinary encounters is unveiled and organized into three main categories: what students think about interdisciplinarity, how they act when being involved in integrations and what external factors are involved in shaping their experience. This paper presents emergent experiential themes, shedding light on both individual and collective experiences, as students navigate and enrich their calculus learning through interdisciplinary connections. Copyright © 2024 Armenta and Dominguez.
COMPARATIVE ANALYSIS OF QUANTITY TAKE-OFF IN CONCRETE, STEEL BARS AND FORMWORK IN APARTMENT BUILDINGS BASED ON CAD AND BIM METHODOLOGIES
(International Council for Research and Innovation in Building and Construction, 0025) Saavedra,Rodrigo; Melendez,Walter; Garces, Gonzalo
Building Information Modeling (BIM) prepares the quantity take-off (QTO) of the construction elements, helping in the management of the design and construction process and preparing the 3D visualization of the construction phases. BIM increases efficiency and gives users more control over construction-related tasks. Construction industry professionals are aware of the advantages of BIM, but because the software BIM is expensive and requires staff training, BIM is not yet widely used. The present investigation identifies the New Cycle building as a Case Study, in which inconsistencies were detected in the QTO, compared to the real quantities of budgeted materials, so the interested parties decided to implement BIM in the use of QTO as a mechanism of control. The central question addressed was: If BIM had been implemented at the tender stage, could it have provided benefits to the project? To do this, various parameters were evaluated that allowed a comparative analysis to be carried out between the results obtained through the use of the CAD and BIM methodology in the same project. In addition, the work processes associated with both methodologies were studied and the perception of CAD and BIM users in the Architecture, Engineering & Construction (AEC) industry was analyzed through the Delphi method. Using the Analytical Hierarchy Process (AHP) method, it was possible to evaluate and compare the two alternatives, CAD and BIM, in order to determine which of them would have been more effective in satisfying the objectives set in the project, considering various variables, both technical and economical. The study highlights the advantages of BIM over CAD for QTO in construction projects, providing valuable information for informed decision making in future projects. However, BIM adoption faces challenges such as the need for specialized training, industry resistance to change, complex workflows, and investments in software and hardware. To overcome these barriers, it is recommended to implement comprehensive training programs, foster a culture of innovation and collaboration, simplify BIM-QTO workflows, and explore scalable and accessible technological solutions. © 2025 The author(s).
Rapid decline in extratropical Andean snow cover driven by the poleward migration of the Southern Hemisphere westerlies
(Nature Research, 2024-12) Cordero, Raúl R.; Feron, Sarah; Damiani, Alessandro; MacDonell, Shelley; Carrasco, Jorge; Pizarro, Jaime; Karas, Cyrus; Jorquera, Jose; Sepulveda, Edgardo; Cabello, Fernanda; Fernandoy, Francisco; Wang, Chenghao
Seasonal snow in the extratropical Andes is a primary water source for major rivers supplying water for drinking, agriculture, and hydroelectric power in Central Chile. Here, we used estimates from the Moderate Resolution Imaging Spectroradiometer (MODIS) to analyze changes in snow cover extent over the period 2001–2022 in a total of 18 watersheds spanning approximately 1,100 km across the Chilean Andes (27–36°S). We found that the annual snow cover extent is receding in the watersheds analyzed at an average pace of approximately 19% per decade. These alarming trends have impacted meltwater runoff, resulting in historically low river streamflows during the dry season. We examined streamflow records dating back to the early 1980s for 10 major rivers within our study area. Further comparisons with large-scale climate modes suggest that the detected decreasing trends in snow cover extent are likely driven by the poleward migration of the westerly winds associated with a positive trend in the Southern Annular Mode (SAM).
How Difficult are Simple Electrical Circuit Conceptions? New Findings
(Eurasian Society of Educational Research, 2023) Quezada-Espinoza, Monica; Dominguez, Angeles; Zavala, Genaro
Research on conceptual understanding is one of the first steps in designing materials to improve learning. Literature reports that students have difficulties analyzing and describing phenomena in electric circuits. This report contributes to students' conceptual difficulties regarding simple electrical circuits by systematically analyzing an open conceptual test answered by 531 first-year engineering students. We found students' reasoning that has not yet been reported in the literature as misconceptions or difficulties. To deepen our understanding of students' difficulties, we chose five students by convenience to interview. We present evidence that there are two main contributions to the taxonomy in this study: the Series Circuit Misconception, which is when students convey that the current through bulbs is the same because they are in series, using that as a mnemonic ignoring any change in the circuit; and the Inverse Parallel Circuit Misconception, that is when students mention that the resistance of the circuit decreases when disconnecting bulbs in parallel, neither are reported in the literature. The results of this study have implications for physics education research in electric circuits and educational practice in the classroom. © 2023 The Author(s).
Long-lived particle phenomenology in one-loop neutrino mass models with dark matter
(Springer Science and Business Media Deutschland GmbH, 0025-02) Arbeláez, Carolina; Cottin, Giovanna; Helo, Juan Carlos; Hirsch, Martin; de Melo, Téssio B.
Neutrino masses and dark matter (DM) might have a common origin. The scotogenic model can be considered the proto-type model realizing this idea, but many other variants exist. In this paper we explore the phenomemology of a particular DM neutrino mass model, containing a triplet scalar. We calculate the relic density and check for constraints from direct detection experiments. The parameter space of the model, allowed by these constraints, contains typically a long-lived or quasi-stable doubly charged scalar, that can be searched for at the LHC. We reinterpret existing searches to derive limits on the masses of the scalars of the model and estimate future sensitivities in the high-luminosity phase of the LHC. The searches we discuss can serve to constrain also many other 1-loop neutrino mass models. © The Author(s) 2025.
Environmental assessment of formal and informal waste treatment of liquid crystal display (LCD) monitors
(Elsevier B.V., 2025-01-25) Labra Cataldo, Nicolás; Gallego-Schmid, Alejandro; Muñoz, Edmundo; McLachlan, Carly
In Santiago, Chile, 315,000 liquid crystal display (LCD) monitors are discarded annually. Of this amount, the formal sector of refurbishment and recycling manages only 5 %, creating the conditions for the emergence of informal management systems. This study provides the first comprehensive environmental and circularity assessment of monitor treatment across multiple impact categories, identifying trade-offs associated with formal and informal operations. For this, a life cycle assessment approach is utilised at both the product-level and the municipal management systems level, addressing the processes from the collection of the monitor to its end-of-life. At the product-level, two formal and two informal routes for managing an LCD monitor were evaluated. The results reveal that formal treatment companies have the best environmental performance in all the midpoint categories of ReCiPe, achieving benefits 42,000 times greater than formal disposal for marine eutrophication, and 25 % better than informal flea market traders across all categories. The analysis of management processes attributes most environmental benefits to refurbishment, representing between 76 % and 99 % of the magnitude of the assessed environmental impacts. A sensitivity analysis shows that the environmental performance of an informal trader surpasses that of a formal treatment company when both offer the same expected lifespan for a refurbished monitor and maintain their respective refurbishment rates offered. The municipal-level analysis was carried out through the evaluation of three scenarios. The results indicate that the scenario in which the informal sector cooperates with the formal sector and exclusively dedicates to collecting monitors exhibits superior environmental performance, averaging environmental benefits that are ten times greater than the current scenario and achieving valorisation rates of 22 %, the highest among the evaluated scenarios. The results of this research contribute to the discussion on formalisation and the promotion of the circular economy in the Global South.
Applying Machine Learning Sampling Techniques to Address Data Imbalance in a Chilean COVID-19 Symptoms and Comorbidities Dataset
(Multidisciplinary Digital Publishing Institute (MDPI), 0025-02) Ormeño-Arriagada, Pablo; Márquez, Gastón; Araya, David; Rimassa, Carla; Taramasco, Carla
Reliably detecting COVID-19 is critical for diagnosis and disease control. However, imbalanced data in medical datasets pose significant challenges for machine learning models, leading to bias and poor generalization. The dataset obtained from the EPIVIGILA system and the Chilean Epidemiological Surveillance Process contains information on over 6,000,000 patients, but, like many current datasets, it suffers from class imbalance. To address this issue, we applied various machine learning algorithms, both with and without sampling methods, and compared them using different classification and diagnostic metrics such as precision, sensitivity, specificity, likelihood ratio positive, and diagnostic odds ratio. Our results showed that applying sampling methods to this dataset improved the metric values and contributed to models with better generalization. Effectively managing imbalanced data is crucial for reliable COVID-19 diagnosis. This study enhances the understanding of how machine learning techniques can improve diagnostic reliability and contribute to better patient outcomes. © 2024 by the authors.
Can climate knowledge enable Warragamba Dam, Sydney, Australia to be used to manage flood risk?
(Institute of Physics, 0023-12) Devanand, Anjana; Pitman, Andy J; Carvajal, Guido; Khan, Stuart J
Dams that serve a dual purpose of water supply and flood mitigation operate to maintain a defined full supply level of water that balances the two conflicting requirements. To optimize the use of available storage space, the full supply level may be adjusted to reflect changing risks of future water shortages and future flood inflows based on known seasonal variations and current observations. The Warragamba Dam in eastern Australia is located upstream of the populated Hawkesbury-Nepean valley which has one of the largest flood exposures in the country. However, the operating protocol of the reservoir does not include provisions to reduce the full supply level of the dam for flood mitigation. Large scale climate indicators that are known to influence the hydroclimate of this region may potentially contain useful information to inform the dual use of this reservoir, but their utility for this purpose has not been studied. Here we explore whether current observations of large-scale climate along with antecedent catchment conditions can be used to estimate the probability of large inflows into the reservoir in the next 3- and 6 months, to aid flood management. We find that the predictors have a substantial influence on the probability of large inflows. The probability differences during opposite predictor phases vary by season and range from 30% to 70%. Our results indicate that considering current climate information to inform dual use of the Warragamba dam has merit. © 2023 The Author(s). Published by IOP Publishing Ltd.
Analysis and comparison of students' conceptual understanding of symmetry arguments in Gauss's and Ampere's laws
(American Physical Society, 2023-01) Campos, Esmeralda; Hernandez, Eder; Barniol, Pablo; Zavala, Genaro
Identifying students' difficulties in understanding Gauss's and Ampere's laws is important for developing educational strategies that promote an expertlike understanding of the field concept and Maxwell's equations of electromagnetic phenomena. This study aims to analyze and compare students' understanding of symmetry when applying Gauss's and Ampere's laws to calculate the electric or magnetic field. We conducted a study to analyze how students reason regarding the symmetry conditions necessary to apply Gauss's or Ampere's laws to calculate the electric or magnetic field in three inverse problems. We applied two open-ended questionnaires with parallel surface features, one for Gauss's law and the other for Ampere's law, to 322 engineering students. The three inverse problems present different scenarios with the common characteristic that there is no sufficient symmetry to solve the electric or magnetic field from its corresponding equation. We analyzed students' answers with a phenomenographic approach, focusing on students' answers to a yes or no question and their reasoning. The main findings of the study are the descriptive categories of understanding and the comparison of the categories between contexts (outcome space). The correct reasoning is identifying the necessary symmetry to apply Gauss's or Ampere's law. The other categories refer to the surface features of each scenario to explain students' answers, applying Gauss's or Ampere's law in an oversimplified way and thinking that it would be possible but more complicated in these scenarios. The descriptive categories are related to some of the difficulties previously reported in the literature with standard problems involving Gauss's and Ampere's laws. However, inverse problems elicited variations in the types of reasoning related to the surface features of the scenarios and their parallel representations. The comparative analysis between the electricity and magnetism contexts allowed for identifying that analyzing currents can be more challenging for students than analyzing point charges. This study's findings can guide introductory and intermediate electricity and magnetism instructors to redirect their approach to Gauss's and Ampere's laws by introducing the analysis of inverse problems. © 2023 authors. Published by the American Physical Society.
Mesalazine solubility in supercritical carbon dioxide with and without cosolvent and modeling
(Nature Research, 0025-12) Sajadian, Seyed Ali; Esfandiari, Nadia; Rojas, Adrián; Hemmati, Salar; Jouyban, Abolghasem; Aguila, Gonzalo; Garlapati, Chandrasekhar
In this study, the solubility of mesalazine in supercritical carbon dioxide with and without cosolvent was carried out for the first time at different temperatures and pressure values ranging from 308 to 338 K and 12 to 30 MPa, respectively. The determined experimental molar solubilities of mesalazine in supercritical carbon dioxide were in the range of 4.41 × 10–5 to 9.97 × 10–5 (308 K), 3.9 × 10–5 to 13.1 × 10–5 (318 K), 3.4 × 10–5 to 16 × 10–5 (328 K) and 3.3 × 10–5 to 18.4 × 10–5 (338 K). Meanwhile, the determined experimental molar solubilities in supercritical carbon dioxide using 2% dimethyl sulfoxide as cosolvent were in the range of 28.22 × 10–5 to 36.2 × 10–5 (308 K), 26.07 × 10–5 to 51.41 × 10–5 (318 K), 25.02 × 10–5 to 69.07 × 10–5 (328 K) and 25.86 × 10–5 to 82.6 × 10–5 (338 K). A novel association model was employed to simulate the solubility data of the binary and ternary systems. Various semiempirical correlations were utilized to calculate the solubility of mesalazine in supercritical carbon dioxide. The new association model was deemed the most superior model, achieving an average absolute relative deviation value of 4.13% without a cosolvent, and 3.36% when a cosolvent was included. © The Author(s) 2025.
Research and Realization of High-Power Medium-Voltage Active Rectifier Concepts for Future Hybrid-Electric Aircraft Generation
(Institute of Electrical and Electronics Engineers Inc., 2021-12) Trentin, Andrew; Sala, Giacomo; Tarisciotti, Luca; Galassini, Alessandro; Degano, Michele; Connor, Peter H.; Golovanov, Dmitry; Gerada, David; Xu, Zeyuan; La Rocca, Antonino; Eastwick, Carol N.; Pickering, Stephen J.; Wheeler, Patrick; Clare, Jon C.; Gerada, Chris
In this article, we describe the research and development of a 3 kV active rectifier for a 4 MW aerospace generator drive system demonstrator. The converter is fed by a multiphase high-speed/high-frequency permanent magnet generator. The main aim of the work is to demonstrate for the first time the feasibility of an MW-class generator system meeting future hybrid-electric propulsion requirements. A concept with multiple and isolated three-phase systems feeding different power buses is proposed to meet the availability requirements. Multiple converters (one for each three-phase system) are connected in series and/or in parallel to achieve the rated power and dc-link voltage. This article describes the key design concepts and the development and testing of the converter to meet the challenging application requirements. Reduced power tests are carried out on a full-scale 4 MW converter prototype, validating the proposed design. The work represents a step forward in terms of voltage, power, and output frequency with respect to the state-of-the-art. © 1982-2012 IEEE.
Mesalazine solubility in supercritical carbon dioxide with and without cosolvent and modeling
(Nature Research, 0025-12) Sajadian, Seyed Ali; Esfandiari, Nadia; Rojas, Adrián; Hemmati, Salar; Jouyban, Abolghasem; Aguila, Gonzalo; Garlapati, Chandrasekhar
In this study, the solubility of mesalazine in supercritical carbon dioxide with and without cosolvent was carried out for the first time at different temperatures and pressure values ranging from 308 to 338 K and 12 to 30 MPa, respectively. The determined experimental molar solubilities of mesalazine in supercritical carbon dioxide were in the range of 4.41 × 10–5 to 9.97 × 10–5 (308 K), 3.9 × 10–5 to 13.1 × 10–5 (318 K), 3.4 × 10–5 to 16 × 10–5 (328 K) and 3.3 × 10–5 to 18.4 × 10–5 (338 K). Meanwhile, the determined experimental molar solubilities in supercritical carbon dioxide using 2% dimethyl sulfoxide as cosolvent were in the range of 28.22 × 10–5 to 36.2 × 10–5 (308 K), 26.07 × 10–5 to 51.41 × 10–5 (318 K), 25.02 × 10–5 to 69.07 × 10–5 (328 K) and 25.86 × 10–5 to 82.6 × 10–5 (338 K). A novel association model was employed to simulate the solubility data of the binary and ternary systems. Various semiempirical correlations were utilized to calculate the solubility of mesalazine in supercritical carbon dioxide. The new association model was deemed the most superior model, achieving an average absolute relative deviation value of 4.13% without a cosolvent, and 3.36% when a cosolvent was included. © The Author(s) 2025.

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