Removal mechanisms of organic and inorganic solutes in raw, upland drinking water by nanofiltration: influence of solute-solute and solute-membrane interactions

Nanofiltration (NF) membranes have been applied successfully for the removal of inorganic and organic pollutants, including micropollutants, from drinking water for the past two decades. However, a complete and quantitative understanding of NF removal mechanisms has yet to be achieved. Quantifying the factors governing solute transport and retention by NF is necessary in order to achieve higher treatment efficiency at a lower cost. The aim of this research was to contribute to the current state of the knowledge of the mechanisms of solute retention and transport by NF membranes. The focus was on evaluating the contribution of solute-solute interactions and solute-membrane interactions on solute removal and transport mechanisms. To the knowledge of the author, at the start of this research there was a lack of understanding of the simultaneous impacts of both interactions on the performance of NF membranes, which renders this research novel. To highlight challenges faced by modern membrane plants and identify inorganic and organic pollutants of interest, a study of water quality in Scotland was carried out. Experiments were performed in dead-end stirred cells using two commercial NF membranes, TFC-SR2 and TFC-SR3 provided by Koch, which were extensively characterized. Radiolabeled Endosulfan (ES, 10 μg/L), manganese (5-1,500 mg/L) and Humic Acids (HA, 5-250 mgC/L) were spiked in synthetic water with background electrolyte (1 mM NaHCO3 and 20 mM NaCl). Calcium (Ca, 2.5 mM) was employed in fouling experiments. The influence of the complexation of solutes with HA on solute retention by NF was for the first time quantified for the solute concentrations employed in this study. It was found that manganese retention was influenced by membrane pore size and charge (solute-membrane interactions) and solute speciation (solute-solute interactions). Complexation of manganese and HA (solute-solute interactions) occurred at alkaline conditions but did not enhance manganese retention. At high pH manganese precipitated as solid MnCO3 and these precipitates achieved high retention (99%), even without the presence of HA. ES retention by NF membrane was controlled by size exclusion (solute-membrane interactions). For the tighter TFC-SR3, whose pore size are smaller than the size of ES, ES retention increased in the presence of HA, while for the looser TFC-SR2, whose pores are bigger than ES diameter, ES retention decreased in the presence of HA. For TFC-SR3 increase of ES retention in the presence of HA was due to size exclusion (solute-membrane interactions) and formation of ES-HA complexes (solute-solute interactions). For TFC-SR2 HA-membrane interactions were dominant with respect to solute-solute interactions, increasing membrane molecular weight cut-off (MWCO) and in turn passage of ES. The influence of pressure (5-15 bar) on ES retention in the presence of HA was systematically investigated. Results showed that ES transport through TFC-SR2 and TFC-SR3 was dominated by convection. For the tighter TFC-SR3 lower permeate flux was responsible for the increase of retention with pressure, while for the looser TFC-SR2 higher permeate flux increased concentration polarisation, decreasing retention with pressure. The presence of HA lowered the permeate flux, resulting in a less pronounced variation of retention with pressure for TFC-SR2 and in constant retention for TFC-SR3. The impact of manganese scaling on the performance of NF membranes was investigated at neutral pH. The effects of inorganic precipitates on flux and solute retention by NF have been so far scarcely studied and the impact of inorganic scaling on micropollutant retention by NF is unknown. Findings from this research indicated that manganese deposits did not foul the membranes but on the contrary enhanced their flux and prevented fouling by HA and Ca. The retention of ES, manganese and HA by membranes through which manganese was previously filtered was found to decrease with respect to solute retention by virgin membranes. Manganese filtration was shown to increase membrane MWCO and hydrophilicity. It was proposed that manganese-membrane interactions caused swelling of the membrane active layer by increasing the membrane free volume. The findings of this research indicated the importance of investigating simultaneously the impacts of solute-solute interactions and solute-membrane interactions to understand and explain transport and removal mechanisms of organic and inorganic contaminants by NF

A model‐based design floating‐point accumulator. Case of study: FPGA implementation of a support vector machine kernel function

Recent research in wearable sensors have led to the development of an advanced platform capable of embedding complex algorithms such as machine learning algorithms, which are known to usually be resource‐demanding. To address the need for high computational power, one solution is to design custom hardware platforms dedicated to the specific application by exploiting, for example, Field Programmable Gate Array (FPGA). Recently, model‐based techniques and automatic code generation have been introduced in FPGA design. In this paper, a new model‐based floating‐point accumulation circuit is presented. The architecture is based on the state‐of‐the‐art delayed buffering algorithm. This circuit was conceived to be exploited in order to compute the kernel function of a support vector machine. The implementation of the proposed model was carried out in Simulink, and simulation results showed that it had better performance in terms of speed and occupied area when compared to other solutions. To better evaluate its figure, a practical case of a polynomial kernel function was considered. Simulink and VHDL post‐implementation timing simulations and measurements on FPGA confirmed the good results of the stand‐alone accumulator

Study of a synchronization system for distributed inverters conceived for FPGA devices

In a multiple parallel-connected inverters system, limiting the circulating current phenomenon is mandatory since it may influence efficiency and reliability. In this paper, a new control method aimed at this purpose and conceived to be implemented on a Field Programmable Gate Array (FPGA) device is presented. Each of the inverters, connected in parallel, is conceived to be equipped with an FPGA that controls the Pulse-Width Modulation (PWM) waveform without intercommunication with the others. The hardware implemented is the same for every inverter; therefore, the addition of a new module does not require redesign, enhancing system modularity. The system has been simulated in a Simulink environment. To study its behavior and to improve the control method, simulations with two parallel-connected inverters have been firstly conducted, then additional simulations have been performed with increasing complexity to demonstrate the quality of the algorithm. The results prove the ability of the method proposed to limit the circulating currents to negligible values

Study of a Synchronization System for Distributed Inverters Conceived for FPGA Devices

In a multiple parallel-connected inverters system, limiting the circulating current phenomenon is mandatory since it may influence efficiency and reliability. In this paper, a new control method aimed at this purpose and conceived to be implemented on a Field Programmable Gate Array (FPGA) device is presented. Each of the inverters, connected in parallel, is conceived to be equipped with an FPGA that controls the Pulse-Width Modulation (PWM) waveform without intercommunication with the others. The hardware implemented is the same for every inverter; therefore, the addition of a new module does not require redesign, enhancing system modularity. The system has been simulated in a Simulink environment. To study its behavior and to improve the control method, simulations with two parallel-connected inverters have been firstly conducted, then additional simulations have been performed with increasing complexity to demonstrate the quality of the algorithm. The results prove the ability of the method proposed to limit the circulating currents to negligible values

FPGA Implementation of an Ant Colony Optimization Based SVM Algorithm for State of Charge Estimation in Li-Ion Batteries

Monitoring the State of Charge (SoC) in battery cells is necessary to avoid damage and to extend battery life. Support Vector Machine (SVM) algorithms and Machine Learning techniques in general can provide real-time SoC estimation without the need to design a cell model. In this work, an SVM was trained by applying an Ant Colony Optimization method. The obtained trained model was 10-fold cross-validated and then designed in Hardware Description Language to be run on FPGA devices, enabling the design of low-cost and compact hardware. Thanks to the choice of a linear SVM kernel, the implemented architecture resulted in low resource usage (about 1.4% of Xilinx Artix7 XC7A100TFPGAG324C FPGA), allowing multiple instances of the SVM SoC estimator model to monitor multiple battery cells or modules, if needed. The ability of the model to maintain its good performance was further verified when applied to a dataset acquired from different driving cycles to the cycle used in the training phase, achieving a Root Mean Square Error of about 1.4%

Numerical simulations challenged on the prediction of massive subhalo abundance in galaxy clusters: the case of Abell 2142

In this Letter we compare the abundance of member galaxies of a rich, nearby ($z=0.09$) galaxy cluster, Abell 2142, with that of halos of comparable virial mass extracted from sets of state-of-the-art numerical simulations, both collisionless at different resolutions and with the inclusion of baryonic physics in the form of cooling, star formation, and feedback by active galactic nuclei. We also use two semi-analytical models to account for the presence of orphan galaxies. The photometric and spectroscopic information, taken from the Sloan Digital Sky Survey Data Release 12 (SDSS DR12) database, allows us to estimate the stellar velocity dispersion of member galaxies of Abell 2142. This quantity is used as proxy for the total mass of secure cluster members and is properly compared with that of subhalos in simulations. We find that simulated halos have a statistically significant ($\gtrsim 7$ sigma confidence level) smaller amount of massive (circular velocity above $200\,{\rm km\, s^{-1}}$) subhalos, even before accounting for the possible incompleteness of observations. These results corroborate the findings from a recent strong lensing study of the Hubble Frontier Fields galaxy cluster MACS J0416 \citep{grillo2015} and suggest that the observed difference is already present at the level of dark matter (DM) subhalos and is not solved by introducing baryonic physics. A deeper understanding of this discrepancy between observations and simulations will provide valuable insights into the impact of the physical properties of DM particles and the effect of baryons on the formation and evolution of cosmological structures.Comment: 8 pages, 2 figures. Modified to match the version published in ApJ

Análisis de la producción científica sobre la utilización de actividades grupales en el trabajo del enfermero en Brasil: 1980 a 2003

Dentre as atividades do enfermeiro, muitas estão organizadas no contexto grupal. A constatação de que não havia estudo sistematizado, no Brasil, que oferecesse parâmetro para compreender como o enfermeiro utiliza esse recurso, motivou o desenvolvimento deste estudo, cujo objetivo foi analisar a produção científica sobre a utilização da atividade grupal, relacionada ao trabalho do enfermeiro entre 1980/2003. Pesquisa descritiva/exploratória, realizada por meio de investigação bibliográfica em periódicos nacionais, tendo como base um protocolo específico. Identificou-se 151 artigos que foram analisados quanto à expansão desse conhecimento e às diversas situações em que o grupo é utilizado nas atividades do enfermeiro. Na análise qualitativa, realizada a partir de categorias pré-definidas, identificou-se que o enfermeiro tem utilizado esse recurso na assistência, produção de conhecimento e formação de recursos humanos. A investigação permitiu traçar um panorama dessa produção e elaborar um catálogo que identifica aspectos importantes na construção desse conhecimento pela enfermagem brasileira.Entre las actividades del enfermero, muchas están organizadas en el contexto del trabajo en grupo. La constatación de que no había estudio sistematizado, en Brasil, que permitiese un parámetro para comprender como el enfermero utiliza ese recurso, motivó el desarrollo de este estudio, cuyo objetivo fue analizar la producción científica sobre la utilización de la actividad en grupo relacionada al trabajo del enfermero entre 1980/2003. Investigación descriptiva/exploratoria realizada a través de investigación bibliográfica en periódicos nacionales, teniendo como base un protocolo específico. Identificamos 151 artículos que fueron analizados en cuanto a la expansión de ese conocimiento y las distintas situaciones en que el grupo es utilizado en las actividades del enfermero. En el análisis cualitativo, realizado a partir de categorías previamente definidas, identificamos que el enfermero viene utilizando ese recurso en la asistencia, producción de conocimiento y formación de recursos humanos. La investigación nos permitió trazar un panorama de esa producción y elaborar un catálogo que identifica aspectos importantes en la construcción de ese conocimiento por la enfermería brasileña.Among the many and diverse activities carried out by nurses, many are organized within the context of a group approach. The realization that there were no systematized studies in Brazil, capable of providing parameters that would help to understand how nurses use this resource, motivated the authors to develop this study, whose objective was to review scientific literature on the use of group activity, as it relates to the work carried out by nurses, between 1980 and 2003. This was a descriptive/exploratory research developed through a bibliographic review in Brazilian journals, on the basis of a specific protocol. We were able to identify 151 articles that were reviewed in terms of the expansion of this knowledge and the different situations in which a group is used by nurses. The qualitative analysis done on pre-established categories enabled the authors to verify that nurses have been using this technique while delivering care, producing knowledge and developing human resources. This investigation allowed us to outline a panoramic view of this literature and to develop a catalogue, identifying important aspects in the construction of this knowledge by Brazilian nursing personnel

A pH-sensitive stearoyl-PEG-poly(methacryloyl sulfadimethoxine)-decorated liposome system for protein delivery: an application for bladder cancer treatment

Stealth pH-responsive liposomes for the delivery of therapeutic proteins to the bladder epithelium were prepared using methoxy-poly(ethylene glycol)5kDa-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (mPEG5kDa-DSPE) and stearoyl-poly(ethylene glycol)-poly(methacryloyl sulfadimethoxine) copolymer (stearoyl-PEG-polySDM), which possesses an apparent pKa of 7.2. Liposomes of 0.2:0.6:100, 0.5:1.5:100 and 1:3:100 mPEG5kDa-DSPE/stearoyl-PEG-polySDM/(soybean phosphatidylcholine + cholesterol) molar ratios were loaded with bovine serum albumin (BSA) as a protein model. The loading capacity was 1.3% w/w BSA/lipid. At pH 7.4, all liposome formulations displayed a negative zeta-potential and were stable for several days. By pH decrease or addition to mouse urine, the zeta potential strongly decreased, and the liposomes underwent a rapid size increase and aggregation. Photon correlation spectroscopy (PCS) and transmission electron microscopy (TEM) analyses showed that the extent of the aggregation depended on the stearoyl-PEG-polySDM/lipid molar ratio. Cytofluorimetric analysis and confocal microscopy showed that at pH 6.5, the incubation of MB49 mouse bladder cancer cells and macrophages with fluorescein isothiocyanate-labelled-BSA (FITC-BSA) loaded and N-(Lissamine Rhodamine B sulfonyl)-1, 2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine triethylammonium salt (rhodamine-DHPE) labelled 1:3:100 mPEG5kDa-DSPE/stearoyl-PEG-polySDM/lipid molar ratio liposomes resulted in a time-dependent liposome association with the cells. At pH 7.4, the association of BSA-loaded liposomes with the MB49 cells and macrophages was remarkably lower than at pH 6.5. Confocal images of bladder sections revealed that 2 h after the instillation, liposomes at pH 7.4 and control non-responsive liposomes at pH 7.4 or 6.5 did not associate nor delivered FITC-BSA to the bladder epithelium. On the contrary, the pH-responsive liposome formulation set at pH 6.5 and soon administered to mice by bladder instillation showed that, 2 h after administration, the pH-responsive liposomes efficiently delivered the loaded FITC-BSA to the bladder epitheliu

Radial velocities of five globular clusters obtained with AAOmega

Using the recently commissioned multi-object spectrograph AAOmega on the 3.9m AAT we have obtained medium-resolution near-infrared spectra for 10,500 stars in and around five southern globular clusters. The targets were 47 Tuc, M12, M30, M55 and NGC 288. We have measured radial velocities to +/- 1 km/s with the cross correlation method and estimated metallicity, effective temperature, surface gra vity and rotational velocity for each star by fitting synthetic model spectra. An analysis of the velocity maps and velocity dispersion of member stars revealed systemic rotation in four of the target clusters.Comment: 4 pages, 6 figures, accepted for publication by Astronomische Nachrichte

Creative design of silent codes: braille systen as an example

[EN] Sonia Torres · http://dx.doi.org/10.4995/eme.2017.6887129TRANSLATED ARTICLES CREATIVE DESIGN OF SILENT CODES; BRAILLE SYSTEM AS AN EXAMPLESonia TorresArtist, musician and researcherThis article presents a brief descriptive analysis of some relevant projects where braille is under-stood as a metaphorical concept of visual silence, as a gaze capable of seeing through other senses. The work shows a selection of illustrated books and tactile works with the objective of offering the inclusive meeting between seer and blind. We are always accustomed to a visual reading, but what if we used our hands; touch and other senses? Our motivation is to contribute to new areas, in an interest to highlight the need for a tangible world, a new way of imagining and look-ing at reality. Finally, the text raises a point of reflection to the technological advance as a new frontier of accessibility, we observe important developments that allow to construct graphic communication proposing sensory experiences and moments of interaction[ES] Este artículo presenta un breve análisis descriptivo de algunos proyectos relevantes donde se utiliza el braille entendido desde un concepto metafórico de silencio visual, como una mirada capaz de ver a través de otros sentidos. El trabajo muestra una selección de libros ilustrados y obras táctiles con el objetivo de ofrecer el encuentro inclusivo entre vidente e invidente. Estamos acostumbrados siempre a una lectura visual, pero ¿y si utilizásemos las manos y otros sentidos? Nuestra motivación es contribuir hacia nuevas áreas en un interés por resaltar la necesidad de un mundo tangible, una nueva forma de imaginar y mirar la realidad. Finalmente, el texto plantea un punto de reflexión al avance tecnológico como nueva frontera de accesibilidad, observamos desarrollos importantes que permiten construir la comunicación gráfica proponiendo experiencias sensoriales y momentos de interacción.Torres Cantón, S. (2017). El uso creativo en diseño a través de códigos en silencio; el braille como ejemplo. EME Experimental Illustration, Art & Design. (5):78-85. doi:10.4995/eme.2017.6887.SWORD78855Ackerman, D.: Una historia natural de los sentidos, Traducción de César Aira, Barcelona, Anagrama, 1992.De CÓRDOBA, MARÍA JOSÉ; RICCÒ, DINA; DAY, SEAN: Synaesthesia: Theoretical, artistic and scientific foundations, Granada, Fundación Internacional Artecittà, 2014.Le BRETON: El silencio, aproximaciones, Madrid, Sequitur, 2009.Munari, BRUNO: Verbale Scritto, Mantova, Corraini, 1982.Munari, BRUNO: I laboratori tattili, Mantova, Corraini, 2004.Oyarzabal, CRISTINA: Ciegos: El maravilloso mundo de la percepción, Buenos Aires, Lugar Editorial, 2011.Pallasmaa JUHANI: Los ojos de la piel, Barcelona, Gustavo Gili, 2006