A feedback control system with reference governor for a solar membrane distillation pilot facility

This work presents the development of a feedback control system for a pilot membrane distillation facility powered with solar energy located at Plataforma Solar de Almería (PSA), Spain. The control system allows to fix a suitable operating temperature at the inlet of the distillation system, improving the operation quality. Four direct control schemes based on Proportional Integral (PI) controllers and Feedforward (FF) are designed as well as a reference governor which generates temperature references for the heat generation circuit direct control layer. Simulations and experimental tests are shown to demonstrate the effectiveness of the proposed scheme

A shrinking horizon model predictive control for landing of reusable launch vehicles

The recent advancements of the onboard computational capabilities enable the deployment of GNC algorithms to perform autonomous decisions and complex operations in the final stages of a landing manoeuvre of Reusable Launch Vehicles (RLV). In most cases, such algorithms embed model predictive schemes to optimize during flight by offering a wider versatility compared to classical schemes and the capabilities of identifying potential future behaviours and risks for the mission. Applications such as the vertical landing of reusable launchers (i.e. SpaceX Falcon 9, and Blue Origin New Shepard) and planetary landers (NASA Perseverance) are currently operating or under development by considering the potential benefits of such a technology. A shrinking horizon Model Predictive Control (MPC) is proposed for the guidance and control of RLV during powered descent phases. Standard MPC schemes use receding horizons where the optimal controls are calculated during constant time-length intervals. The direct implementation of such schemes leads to a hovering-like behaviour of the vehicle, which will never reach the landing platform as the final time of landing is always postponed at each iteration step. The solution proposed in this paper consists on implementing an MPC algorithm that calculates and updates the optimal thrust profile along time-dependent decreasing horizons. The algorithm updates and adapts the time-length of the receding horizon as a function of a time-scaling factor and the time that has passed since the last MPC iteration. It introduces a new concept called terminal horizon, which determines the maximum time in which the RLV must be landed. The optimal solutions are found through convex optimisation algorithms. Numerical simulations and results show an enhanced performance of the guidance scheme and validate the idea that a decreasing horizon is more suitable than a receding one in a powered descent scenario. Monte Carlo and Parametric analyses are performed to assess the performance of the proposed algorithm in a landing test case scenario. This simulated case considers the disturbances caused by Earth’s atmosphere drag force in interaction with a descending first stage of SpaceX Falcon 9 rocket. This study demonstrates the applicability of the proposed MPC technique identifying feasibility boundaries for tuning the MPC parameters and determining the range of initial conditions that allow for a successful landing

Prediction models to analyse the performance of a commercial-scale membrane distillation unit for desalting brines from RO plants

Desalting brines from Reverse Osmosis (RO) plants is one of the most promising applications of Membrane Distillation (MD) systems. The development of accurate models to predict MD system performances plays a significant role in the design of this kind of industrial applications. In this paper, a commercial-scale Permeate-Gap Membrane Distillation (PGMD) module was modelled by means of two different approaches: Response Surface Methodology (RSM) and Artificial Neural Networks (ANN). Condenser inlet temperature, evaporator inlet temperature, feed flow rate and feed water salt concentration were selected as inputs of the model, while permeate flux and Specific Thermal Energy Consumption (STEC) were chosen as responses. The prediction abilities of both RSM and ANN models were compared with further experimental data by using the Analysis of Variance (ANOVA) and the Root Mean Squared Error (RMSE). The results show that the ANN model is able to predict in a more precise way the behaviour of the module for the whole range of input variables. Thus, ANN model was used to find the optimal operating conditions, for the module operating at feed water salinity of 70 and 105 g/L, concentrations that can be reached when desalting RO brines

La intervención docente en el aula de educación física

El trabajo presentado se centra en la intervención docente en el aula de Educación Física y en el análisis del clima motivacional generado. El trabajo se divide en dos partes, el marco teórico y la parte práctica. El marco teórico se centra principalmente en la teoría de las metas de logro, aunque también se desarrollan otros aspectos relacionados con el clima motivacional. En la parte práctica, se realiza un análisis de una serie de sesiones previamente grabadas y se realizan comentarios y propuestas de mejora con respecto a los resultados obtenidos

A chemosensor for dihydrogenphosphate based on an oxoazamacrocycle possessing three thiourea arms

We report a new H-bond macrocyclic chromogenic chemosensor in organic media, H3L, which displayed drastic changes in its UV–vis spectra revealing selectivity for dihydrogenphosphate over other inorganic anions, such as acetate or fluoride. The X-ray crystal structures of the [H4L⋯NO3]·(CH3CN)4 and [H4L⋯CF3CO2]·(CH3CN)2 salt complexes are also reportedR. B. thanks the Xunta de Galicia (Spain), Projects PGIDI10PXIB209028PR and INCITE09E1R209058ES. M. V. L. thanks the Directorate-General for Research and Development of the Xunta of Galicia (INCITE09 209 084 PR) and the Ministry for Science and Innovation of Spain (CTQ2009-14431/BQU) for financial supportS

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes.

peer reviewedThe synthesis of zwitterionic dithiocarboxylate adducts was achieved by deprotonating various aldiminium or 1,2,3-triazolium salts with a strong base, followed by the nucleophilic addition of the in situ-generated cyclic (alkyl)(amino) or mesoionic carbenes (CAACs or MICs) onto carbon disulfide. Nine novel compounds were isolated and fully characterized by 1H and 13C NMR, FTIR, and HRMS techniques. Moreover, the molecular structures of two CAAC·CS2 and two MIC·CS2 betaines were determined by X-ray diffraction analysis. The analytical data recorded for all these adducts were compared with those reported previously for related NHC·CS2 betaines derived from imidazolinium or (benz)imidazolium salts. Due to the absence of electronic communication between the CS2 unit and the orthogonal heterocycle, all the CAAC·CS2, MIC·CS2, and NHC·CS2 zwitterions displayed similar electronic properties and featured the same bite angle. Yet, their steric properties are liable to ample modifications by varying the exact nature of their cationic heterocycle and its substituents

Control predictivo para la operación eficiente de una planta formada por un sistema de desalación solar y un invernadero

Jornadas de Automática (37ª. 2017. Gijón

REVIT: una herramienta con interoperabilidad BIM [2009]

En el ámbito de las nuevas tecnologías, los autores nos presentan un interesante artículo sobre “REVIT: Una herramienta con interoperabilidad BIM”, en él nos indican que el proceso de elaboración de estimaciones implica la integración de una gran cantidad de información. Y que, en las empresas constructoras pequeñas, el superintendente es el responsable de integrar dicha información, de manera que, durante la elaboración de estimaciones, la supervisión de la construcción se realiza de manera paralela. No es extraño, que ambas tareas no sean realizadas adecuadamente. Debido a estas condiciones, se pueden producir errores tales como olvidos de cuantificación de volúmenes y conceptos de obra, así como cobros en exceso. Este estudio se basa en la detección y desarrollo de una herramienta computacional que mejore el proceso de elaboración de estimaciones en algunas de las áreas de: captura de datos en obra, generadoras, reportes fotográficos, transferencia de datos, etcétera., razón por la cual queda clasificado como un desarrollo tecnológico. El proceso que se obtendrá será aplicable a una empresa constructora pequeña tipo que tenga como nicho de mercado a alguna de las dependencias de gobierno: Ayuntamiento de Mérida, ICEMAREY o SDUOPV. La metodología propuesta se ha dividido en cuatro partes principales: documentación del proceso actual de elaboración de estimaciones, identificación de las partes del proceso susceptibles de mejora, identificación y propuesta de la herramienta computacional y prueba de la herramienta computacional