Catalyser production with microstructured components

La tesis describe un método completamente nuevo sobre la aplicación de este micro-tecnología en la producción de los catalizadores, específicamente NH4-dawsonite. Las soluciones acuosas utilizadas para precipitar el material se define como nonahidrato nitrato de aluminio y carbonato de amonio. La preparación del mineral análogo se realizó por primera vez dentro de un micro-mezclador de acero inoxidable (CPMM 1200/8) con un volumen de 78μl y un principio de mezcla “split-recombine”, optimizando los parámetros del proceso para un tiempo de producción continuo que, en este caso, es significativamente afectado por la obstrucción del micro-canal. Además, la síntesis se realizó dentro del micro-sistema presurizado y se han propuesto otro tres diferentes geometrías del micro-canal: en forma de T de acero inoxidable, el poly (metylmetacrylate) (PMMA) spilt-recombine del micromixer Caterpillar y en forma de Y la unión de PMMA dos regímenes diferentes de mezcla (perfecta (spilt-recombine) / imperfecto (T / Y en forma de microsistemas)) con el objetivo de minimizar la obstrucción del canal. El enfoque de unión-Y se ha demostrado ser la mejor alternativa para reducir al mínimo la deposición de partículas en la pared del canal, lo que implica un mejor control del fenómeno de obstrucción, al estar totalmente eliminado. Esto representa un paso adelante en el proceso de intensificación con beneficios en la industria. Al superar este paso, la posibilidad de transferir esta nueva tecnología en la industria es cada vez más tangible a convertirse en realidad.The thesis presents a new approach regarding the application of microtechnology in production of catalysts, specifically NH4-dawsonite by using microreactor technology. The aqueous solutions used to precipitate the material were defined as aluminium nitrate nonahydrate and ammonium carbonate. The mineral analogue preparation was first held within a 78μl volume split-recombine stainless steel micromixer (CPMM 1200/8 mixer) by optimizing the process parameters for a continuous time of production which in the present case is significantly affected by the channel clogging. Further, the synthesis was carried out within a pressurized micro-system and different geometries of the microchannel: T-shaped stainless steel, poly(metylmetacrylate) (PMMA) spilt-recombine Caterpillar micromixer and Y-shaped PMMA junction with two different mixing regimes (perfect (spli-recombine)/imperfect (T/Y-shaped microsystem)) with the aim of minimizing the clogging. The Y-junction approach was demonstrated to be a great alternative for minimizing the particle deposition on channel’s wall, clogging phenomenon being totally removed. This represents a significant step forward in process intensification with benefits within the industry. Over passing this step the possibility to transfer this new technology into industry is more and more tangible to become reality

Brain activity changes on healthy adults during variable-g maneuvers

Filiació URV: SI COMPTE! Nota pel CRAI: el considerem article o pòster? Forma part de: Proceedings of the 18th World Congress of Psychophysiology (IOP2016) of the International Organization of Psychophysiology (IOP) Havana, Cuba August 31st to September 4th, 2016 A Scopus buscant-lo pel DOI no dóna resultats.In the last years increased attention directed towards the effect of the hyper/hypogravity on human body was reported, due to the great interest in raising the spatial mission. To understand the effect of short weightlessness periods on psychophysiological changes in human brain activity of normal healthy subjects, and how these changes may affect psychologically the person, present work reports the results obtained during a parabolic flight campaign effected using a small aerobatic plane. This aspect could help in the human survival within unsuitable environments. To perform the experiments, a small CAP10B single-engine aerobatic plane has been proposed and six healthy volunteers had accepted the challenge. The parabolic flight is characterized by gravity variations from 1g to approximately 3g, so called hypergravity phase, or reduced gravity down to 0.5g, so called hypogravity phase. During the flight the plain performed 12 parabolas in total, describing two types of experiments: within the first six parabolas the individuals had their eyes open and in the last six, the eyes closed. Electrocardigram, electroencephalogram, and oxygen content in the blood have been continuously recorded during the entire flight for all volunteers. In earlier work [Dubert et al. 2015] we discovered that changes of brain cortical activity involving the visual cortex and the limbic system are detected when the person sight is minimized. Concerning EEG data, the global intracortical activity, by lobes, was as well, for the first time presented as a temporal evolution along the parabola. Same temporal evolution comparison of physiological and phychological changes in human brain under hypo/hypergravity conditions, respectively and for different healthy subjects is proposed within present re

Characterization of the accelerometric environment of DCMIX2/3 experiments

publicat online https://doi.org/10.1007/s12217-018-9640-7A comparative analysis of the vibratory environment of the DCMIX2/3 thermodiffusion experiments is presented here by using acceleration signals coming from different sensors placed in the Destiny, Columbus and Kibo modules. The es03 sensor, nearest to the experimental device and located inside the Glovebox (Destiny module) has been defined as reference. Data were downloaded from the NASA PIMS website paying special attention to the runs coinciding with disturbances such as dockings or extravehicular activities (EVAs) as they could particularly affect the International Space Station (ISS) microgravity levels. The analyses have been made minute by minute for the three acceleration components by using the Frequency Factor Index (FFI), Spectral Entropy (SEN) and Root Mean Square (RMS) values evaluated over one-third-octave frequency bands. Spearman's rank correlation coefficient and the coherence function have been used to investigate the degree of linear correlation between the reference signal and the other ones. SEN evolution showed different patterns compared to the reference. Also, RMS values surpassing the ISS microgravity limits were detected in all sensors, mainly at low frequency bands (<10 Hz) and prevailing on zA direction. However the sensors located in the Destiny module better accomplished the ISS vibratory limits requirements. Finally, some degree of linear correlation at structural frequencies (< 3Hz) has also been detected. Overall, the sensors placed in the Destiny, Columbus and Kibo modules presented different vibratory characteristics and, despite they offer valuable information of the whole environment, may not be sufficient properly characterize DCMIX2/3 experiments

Onsite vibrational characterization of DCMIX2/3 experiments

The SODI-DCMIX thermodiffusion series experiments are part of the fluid research program carried out by the European Space Agency on board of the International Space Station (ISS). In particular, DCIMIX2/3 were conducted in the past inside the Microgravity Science Glovebox in the US Laboratory. Due to the physical nature of the processes implied, these kind of runs were very long and particularly delicate because the low vibratory limit requirements must be maintained for hours. This restrictive condition not always is achieved, therefore, an accurate surveillance of the acceleration levels along the different experiments is necessary, to ensure a correct interpretation of the experimental results. This work analyzes onsite vibrational environment of DCMIX2/3 covering the periods in which the experiments were going on. To do so, acceleration signals only coming from the es03 sensor, nearest to the experimental equipment and located in the Glovebox, were downloaded from the PIMS NASA website. To be as precise as possible the signals have always been treated minute by minute. To detect the transient disturbances along the experiments, several warnings were considered. First, 1 min RMS values, for the three acceleration components were evaluated, in time and in frequency domain. Additional information was obtained by plotting the power spectral densities of the signals, PSD, and their spectrogram with the aim of characterizing long periods of acceleration data. Due to great influence of low frequencies in this type of experiments, the Frequency Factor Index, FFI, was evaluated each minute. Complementary, the spectral entropy evolution was proposed as a fast new indicator of external perturbations. It has been found a good correlation between the spectrogram, temporal RMS and spectral entropy. Finally, a graphic representation of the points associated to the 1-min RMS values in one-third-octave frequency intervals which exceed the ISS limit curve requirements, was considered as a new and easy strategy for depicting the warnings that recognize the main disturbances along the experiment.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Separation under thermogravitational effects in binary mixtures

In the present work, by using a parallelepipedic thermogravitational microcolumn, the temperature gradient influence on the stability of the flow has been examined, emphasizing mixtures with positive Soret coefficients. Experiments were conducted for DCMIX2 Toluene/Methanol and DCMIX3 Water/Ethanol binary subsystems because of their broad range of positive Soret values for high concentrations of methanol and ethanol, respectively. Two different mixtures have been studied here in order to confirm the thermogravitational stability of the mixtures. Experiments were compared with numerical simulations carried out using the open-source software platform OpenFOAM

Characterization of the Accelerometric Environment of DCMIX2/3 Experiments

A comparative analysis of the vibratory environment of the DCMIX2/3 thermodiffusion experiments is presented here by using acceleration signals coming from different sensors placed in the Destiny, Columbus and Kibo modules. The es03 sensor nearest to the experimental device and located inside the Glovebox (Destiny module) has been defined as reference. Data were downloaded from the NASA PIMS website paying special attention to the runs coinciding with disturbances such as dockings or extravehicular activities (EVAs) as they could particularly affect the International Space Station (ISS) microgravity levels. The analyses have been made minute by minute for the three acceleration components by using the Frequency Factor Index (FFI), Spectral Entropy (SEN) and Root Mean Square (RMS) values evaluated over one-third-octave frequency bands. Spearman’s rank correlation coefficient and the coherence function have been used to investigate the degree of linear correlation between the reference signal and the other ones. SEN evolution showed different patterns compared to the reference. Also, RMS values surpassing the ISS microgravity limits were detected in all sensors, mainly at low frequency bands (< 10 Hz) and prevailing on zA direction. However the sensors located in the Destiny module better accomplished the ISS vibratory limits requirements. Finally, some degree of linear correlation at structural frequencies (< 3 Hz) has also been detected. Overall, the sensors placed in the Destiny, Columbus and Kibo modules presented different vibratory characteristics and, despite they offer valuable information of the whole environment, may not be sufficient to properly characterize DCMIX2/3 experiments.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

On the Monitoring of the Vibratory Environment of DCMIX4 Campaign. Preliminary Results

This work presents the preliminary characterization of the vibrational environment of the DCMIX4 thermodiffusion experiment conducted onboard the ISS from December 2018 to March 2019. Given the long duration of each one of the 58 runs of the campaign and to ensure a correct interpretation of the results, an accurate analysis of acceleration levels all along the experiment is advisable. Digital signals coming from the nearest sensor, es09006, located in the Microgravity Science Glovebox (Destiny module) were downloaded from the PIMS NASA website. The techniques used to identify the main disturbances during the experiments were defined both in time and frequency domains. It is expected that the results obtained can help the experimentalist to have an overview of the possible sources of disturbances that may affect their experiments. To visualize the possible impact of the accelerometric environment on the experiment a numerical simulation has been performed. Four signals have been chosen, one considering the ideal case g = 0, one coming from the OSS raw sensor (outside the Microgravity Science Glovebox) and the other two, coming from the es09006 sensor that needed to be mathematical manipulated for considering only the low frequency range. Independent of the location of the sensor, numerical simulations do not detect, in any case, appreciable flow disturbances if quiescent periods are considered. Therefore, in case the reference sensor is not available one can use other sensors placed in the same module.SCOPUS: ar.jDecretOANoAutActifinfo:eu-repo/semantics/publishe

On the Monitoring of the Vibratory Environment of DCMIX4 Campaign. Preliminary Results

This work presents the preliminary characterization of the vibrational environment of the DCMIX4 thermodiffusion experiment conducted onboard the ISS from December 2018 to March 2019. Given the long duration of each one of the 58 runs of the campaign and to ensure a correct interpretation of the results, an accurate analysis of acceleration levels all along the experiment is advisable. Digital signals coming from the nearest sensor, es09006, located in the Microgravity Science Glovebox (Destiny module) were downloaded from the PIMS NASA website. The techniques used to identify the main disturbances during the experiments were defined both in time and frequency domains. It is expected that the results obtained can help the experimentalist to have an overview of the possible sources of disturbances that may affect their experiments. To visualize the possible impact of the accelerometric environment on the experiment a numerical simulation has been performed. Four signals have been chosen, one considering the ideal case g = 0, one coming from the OSS raw sensor (outside the Microgravity Science Glovebox) and the other two, coming from the es09006 sensor that needed to be mathematical manipulated for considering only the low frequency range. Independent of the location of the sensor, numerical simulations do not detect, in any case, appreciable flow disturbances if quiescent periods are considered. Therefore, in case the reference sensor is not available one can use other sensors placed in the same module.The present work has been supported by grants ESP2017-83544-C3-1-P (MCIU/FEDER) and 2018PFR-URV-B2-73 (Rovira i Virgili University)