Diseño, modelamiento, simulación e implementación de un sistema de levitación magnética (Maglev) con un grado de libertad

In the present work, a magnetic levitation system (maglev) with one degree of freedom (vertical) is designed, simulated and implemented physically. A simplified linear model is first obtained which describes the system. From this model, linear controllers are designed using traditional control methods. We prove these controllers effectiveness to stabilize the system and their performance parameters by simulation. The proposed models are also validated experimentally.En el presente trabajo se diseña, simula e implementa físicamente un sistema de levitación magnética (maglev) con un grado de libertad (vertical). Se deduce teóricamente un modelo simplificado lineal que modela al sistema, a partir del cual se diseñan controladores lineales mediante métodos tradicionales de control. Se prueba la efectividad para estabilizar al sistema y los parámetros de desempeño de dichos controladores mediante simulación. Los modelos propuestos además se validan experimentalmente

An Integration-to-Bound Model of Decision-Making That Accounts for the Spectral Properties of Neural Data

Integration-to-bound models are among the most widely used models of perceptual decision-making due to their simplicity and power in accounting for behavioral and neurophysiological data. They involve temporal integration over an input signal (“evidence”) plus Gaussian white noise. However, brain data shows that noise in the brain is long-term correlated, with a spectral density of the form 1/fα (with typically 1 \u3c α \u3c 2), also known as pink noise or ‘1/f’ noise. Surprisingly, the adequacy of the spectral properties of drift-diffusion models to electrophysiological data has received little attention in the literature. Here we propose a model of accumulation of evidence for decision-making that takes into consideration the spectral properties of brain signals. We develop a generalization of the leaky stochastic accumulator model using a Langevin equation whose non-linear noise term allows for varying levels of autocorrelation in the time course of the decision variable. We derive this equation directly from magnetoencephalographic data recorded while subjects performed a spontaneous movement initiation task. We then propose a nonlinear model of accumulation of evidence that accounts for the ‘1/f’ spectral properties of brain signals, and the observed variability in the power spectral properties of brain signals. Furthermore, our model outperforms the standard drift-diffusion model at approximating the empirical waiting time distribution

Crisis management in public–private partnerships: lessons from the global crises in the XXI century

Purpose: Global crises have become increasingly recurrent events that jeopardize public-private partnerships (PPPs). In this context, the purpose of this paper is to expose the PPP-crisis research agenda by combining bibliometric and network analyses. Design/methodology/approach: The PPP literature associated with global crises between the 2008 global financial crisis and 2022 was analyzed in three stages: (1) paper selection and screening for the inclusion/exclusion of articles relevant to this research, (2) semantic network development for examining thematic relationships among selected papers by considering the co-occurrence of keywords within the chosen studies and (3) calculation of network metrics for analysis. Findings: The paper identified six research avenues for the PPP-crisis agenda: public interest, relational governance, risk management, user-pay PPPs, crisis management and financial performance. The PPP-crisis literature has spread significantly in the last five years driven by the case study approaches on a national or regional basis. Conversely, non-crisis periods generate room to strengthen user-pay PPPs and relational governance. The pandemic and post-pandemic times shared the priorities of the 2008 financial crisis but also strengthened the management of the risks and the structural drivers of the global crisis. Originality/value: This study demonstrates that during global crisis periods, the public interest and financial performance gain relevance in a detriment of structural solutions to social legitimacy erosion of PPPs because of the urgency of giving tools to the public and private sectors to tackle the financial issues, which steer future issues for PPPs

Operation and physics of photovoltaic solar cells: an overview

Solar energy is considered the primary source of renewable energy on earth; and among them, solar irradiance has both, the energy potential and the duration sufficient to match mankind future energy needs. Nowadays, despite the significant potential of sunlight for supplying energy, solar power provides only a very small fraction (of about 0.5%) of the global energy demand. In order to increase the worldwide installed PV capacity, solar photovoltaic systems must become more efficient, reliable, cost-competitive and responsive to the current demands of the market. In this context, PV industry in view of the forthcoming adoption of more complex architectures requires the improvement of photovoltaic cells in terms of reducing the related loss mechanism, focusing on the optimization of the process design, as well as, reducing manufacturing complexity and cost. Hence a careful choice of materials, a suitable architecture and geometric distribution, passivation techniques and the adoption of a suitable numerical modeling simulation strategy are mandatory. This work is part of a research activity on some advanced technological solutions aimed at enhancing the conversion efficiency of silicon solar cells. In particular, a detailed study on the main concepts related to the physical mechanisms such as generation and recombination process, movement, the collection of charge carriers, and the simple analytical 1D p-n junction model required to properly understand the behavior of solar cell structures. Additionally, the theoretical efficiency limits and the main loss mechanisms that affect the performance of silicon solar cells are explained

Aplicación de nuevas organoarcillas en el desarrollo de pinturas epoxicas anticorrosivas

En los actuales momentos la tecnología de los recubrimientos ha tenido un avance muy grande debido a las diferentes investigaciones que se realizan en todo el mundo, especialmente a nivel nanométrico por lo que se han enfocado en la necesidad de desarrollar nuevos materiales poliméricos de alto desempeño. Estos materiales los cuales han sido modificados a nivel nanométrico son requeridos para fabricar recubrimientos con características mecánicas, térmicas y anticorrosivas únicas y superiores a los del compuesto original, serán necesarias para resistir condiciones ambientales agresivas. Este tipo de desafíos han atraído a investigadores e industrias de todo el mundo hacia el nuevo campo de los polímeros híbridos “orgánicos-inorgánicos”. Para este proyecto se utilizan 2 tipos de arcillas tipo montmorillonita tratadas con un surfactante o inhibidor volátil de corrosión. Se fabricarán mezclas con un porcentaje de 3% de nanoarcilla a tres concentraciones diferentes de VCI: 0,1 CEC, 0,5 CEC y 1 CEC. Posteriormente se evaluarán sus propiedades térmicas mediante un Análisis Termogravimétrico (TGA) y por Calorimetría Diferencial de Barrido (DSC), luego se analizará los cambios en la estructura molecular mediante Espectrografía Infrarroja por Transformadas de Fourier (FTIR) y finalmente se comprobara si existió una intercalación o exfoliación de las nanoarcillas en la matriz polimérica mediante la Difractometria de Rayos X (XRD). Con este proyecto, se espera optimizar el rendimiento en uso de las pinturas anticorrosivas y así obtener un mayor beneficio alargando la vida útil de las mismas y por ende la vida útil de las estructuras a las cuales protege

Effect of Butionin-Sulfaximine and Fluphenazine as Trypanothione Inhibitory Drugs on Promastigotes and Axenic Amastigotes of Leishmania Peruviana and Leishmania Braziliensis

Background: Leishmaniasis is a disease caused by the Leishmania parasite, which is difficult to diagnose, causes disfigurement and is difficult to treat. Objectives: To determine the effect of Butionin-Sulfaximine (BSO) and Fluphenazine on trypomastigotes and axenic amastigotes of Leishmania peruviana and Leishmania braziliensis. Methods: A study was performed with Butionin-Sulfaximine (BSO), Fluphenazine, and Glucantime (positive control,) utilizing respective concentrations of 41.7 mg/ml, 4.17 mg/ml, and 50 mg/ml for twenty-four hours on axenic amastigotes. Results: A significant difference (*P < 0.05) was found between the negative control group, Fluphenazine, and BSO within both the axenic amastigotes of L. peruviana (5.5 X 105 / ml for the negative control, 0.15 X 105 / ml for Fluphenazine, and 0.7 X 105 / ml for BSO) and L. braziliensis (6.9 X 105/ml for the negative control, 0.18 X 105/ml for Fluphenazine, and 0.22 X 105/ml for BSO). Another significant difference (*P < 0.05) was found in the promastigotes of L. peruviana (5.9 X 105 / ml for the negative control, 0.66 X 105 / ml for Fluphenazine, and 3.1 X 105 / ml for BSO) and L. braziliensis (8.7 X 105/ml for the negative control and 5.68 X 105/ml for Fluphenazine). Conclusions: From this, we conclude Fluphenazine and BSO present promising antiparasitic effects against axenic amastigotes of L. peruviana and L. braziliensis in both pharmacological tests of the in vivo model and their potential future use

Fragile Heterosexuality: A Cross-cultural Study Between Germany and Italy

Prior research in the UK and the USA found that heterosexual identity was perceived as more easily compromised than gay identity: a finding dubbed the “Fragile Heterosexuality” effect. However, there is as yet no evidence that this effect occurs outside the USA and UK. With representative samples from Germany (N = 1236) and Italy (N = 1249), we investigated the fragile heterosexuality effect using participants’ agreement with gender-neutral statements about the perceived fragility of sexual orientation of others. We found evidence supporting the fragile heterosexuality effect in both countries. We also investigated six possible moderators of the effect. Higher estimates of gay/lesbian population weakened the effect, and higher levels of anti-gay prejudice strengthened the effect. Contact (quantity/quality), right wing authoritarianism, and social dominance orientation did not moderate the effect. These findings contribute to previous literature by highlight that the fragile heterosexuality effect appears across countries of diverse LGBTQ friendliness and languages, and also suggest plausible explanations for the effect

Aplicación de la herramienta Look Ahead para el mejoramiento de la planificación del Centro de Salud Materno Infantil, Pachacútec, Perú - Corea, Ventanilla Callao

El presente estudio de investigación tuvo como propósito fundamental la aplicación de la herramienta Look Ahead, una herramienta de planificación de media categoría: entre la planificación maestra de obra y la planificación semanal, en la ejecución del Centro de Salud Materno Infantil Pachacútec, Perú – Corea, ubicado en el distrito de Ventanilla, Callao, con la finalidad de descubrir en qué medida el Look Ahead de la filosofía Lean Construction (Construcción sin pérdidas) mejora la planificación de obra en la ejecución del proyecto en estudio mediante el análisis de las restricciones y el monitoreo de la producción, con el objetivo de que se logre coordinar el flujo de trabajo para reducir pérdidas e incrementar la capacidad de desarrollar las partidas a ejecutar sin complicaciones, en un futuro medio. En campo se comprobó la aplicación de esta herramienta y tuvo un efecto positivo, dando como resultado un inventario de trabajo listo a realizarse, ahorro en la reducción de costos, de plazos y mejorando la planificación del proyecto, ya que sin la aplicación del Look Ahead, pudo haber concluido en retraso, hecho que ahora es el talón de Aquiles de las empresas dedicadas al rubro de la construcción. El primer paso a realizar, para mejorar la planificación del proyecto es haciendo una sectorización al Block en el que se va a trabajar y en el que intervendrá la aplicación de la metodología Look Ahead. Teniendo esta sectorización se procederá a realizar el tren de actividades para determinar el plazo de ejecución de cada sector. Se trabajó continuamente con el Ing. Residente de Obra y el Ing. De Campo, quienes con su experiencia y conocimientos en lo que respecta a los procesos constructivos, pudimos plasmar los datos en excel para posteriormente llevarlos al formato Look Ahead y así obtener la nueva planificación de obra.The main purpose of this research study was to apply the Look Ahead tool, a medium-level planning tool: between master planning and weekly planning, in the implementation of the Pachacútec Maternal and Child Health Center, Peru - Korea , located in the district of Ventanilla, Callao, with the purpose of discovering to what extent the Look Ahead of the Lean Construction philosophy (Construction without losses) improves the planning of work in the Second Stage of the execution of the project under study through the analysis of the restrictions and the monitoring of the production, with the objective that it is possible to coordinate the work flow to reduce losses and increase the capacity to develop the items to be executed without complications, in a future medium. In the field, the application of this tool was verified and had a positive effect, resulting in a work inventory ready to be carried out, savings in cost reduction and without having to affect compliance with deadlines but improving project planning, since that without the application of the Look Ahead, it could have concluded in delay, fact that now is the Achilles heel of the companies dedicated to the field of the construction. The first step to be taken, to improve the planning of the project, is to make a sectorisation to the Block in which it will work and in which the application of the Look Ahead methodology will intervene. Having this sectorization will proceed to perform the train of activities to determine the execution period of each sector. We worked continuously with the Project Resident Engineer and the Field Engineer, who with their experience and knowledge regarding the construction processes, we were able to capture the data in excel to later take them to the Look Ahead format and thus obtain the new Work planning of the project.Tesi