Humidified Gas Mixture Research Articles

Synthesis ranges for YBaFe4O7 and its topotactic oxidation in ambient air to YBaFeIII4O8.5

Conditions for YBaFe4O7 synthesis from oxide/carbonate amorphous precursors are investigated versus temperature and partial pressure of oxygen at high-temperature equilibrium with the sample in flowing atmosphere of humidified Ar and H2 gas mixtures. Upon topotactic oxidation in ambient air of the cooled-down product, YBaFeIII4O8.5 forms in a couple of minutes. Neutron powder diffraction suggests that added oxygens enter octahedral holes in the cubic closest packing of O and Ba atoms of YBaFe4O7. Up to two oxygen atoms add to some Fe coordination tetrahedra in the kagome-like layer of YBaFe4O7 in a disordered distribution described as partially occupied crystal-structure sites. The oxidized YBaFeIII4O8.5 is metastable and decomposes at high temperatures into FeIII oxides of barium or yttrium. The synthesized YBaFe4O7 is a powerful room-temperature O2 getter that can be reverted by annealing in the above gas mixture.

Understanding the Impact of Sintering Temperature on the Properties of Ni–BCZY Composite Anode for Protonic Ceramic Fuel Cell Application

Understanding the impact of sintering temperature on the physical and chemical properties of Ni-BaCe0.54Zr0.36Y0.1O3-δ (Ni-BCZY) composite anode is worthy of being investigated as this anode is the potential for protonic ceramic fuel cell (PCFC) application. Initially, NiO–BCZY composite powder with 50 wt% of NiO and 50 wt% of BCZY is prepared by the sol–gel method using citric acid as the chelating agent. Thermogravimetric analysis indicates that the optimum calcination temperature of the synthesised powder is 1100 °C. XRD result shows that the calcined powder exists as a single cubic phase without any secondary phase with the lattice parameter (a) of 4.332 Å. FESEM analysis confirms that the powder is homogeneous and uniform, with an average particle size of 51 ± 16 nm. The specific surface area of the calcined powder measured by the Brunauer–Emmett–Teller (BET) technique is 6.25 m2/g. The thickness, porosity, electrical conductivity and electrochemical performance of the screen-printed anode are measured as a function of sintering temperature (1200–1400 °C). The thickness of the sintered anodes after the reduction process decreases from 28.95 μm to 26.18 μm and their porosity also decreases from 33.98% to 26.93% when the sintering temperature increases from 1200 °C to 1400 °C. The electrical conductivities of the anodes sintered at 1200 °C, 1300 °C and 1400 °C are 443 S/cm, 633 S/cm and 1124 S/cm at 800 °C, respectively. Electrochemical studies showed that the anode sintered at 1400 °C shows the lowest area specific resistance (ASR) of 1.165 Ω cm2 under a humidified (3% H2O) gas mixture of H2 (10%) and N2 (90%) at 800 °C. Further improvement of the anode’s performance can be achieved by considering the properties of the screen-printing ink used for its preparation.

Molecular Exclusion Separation of 1‐Butene Isomers by a Robust Metal–Organic Framework under Humid Conditions

AbstractSeparating n‐butene and i‐butene by adsorption is an energy‐efficient alternative, but designing porous adsorbents that distinguish the subtle differences between the isomers is extremely challenging. Currently, adsorbents that can sieve 1‐butene isomers and are stable enough to withstand humid gas mixtures are largely unmet. Herein, we propose a robust ultramicroporous metal–organic framework (MET‐Fe) that can separate 1‐butene isomers through molecular exclusion. The pore aperture size (4.6 Å) precisely matches the kinetic diameters of the isomers, as verified by static and kinetic adsorption experiments and theoretical calculations. Furthermore, dynamic breakthrough experiments confirmed the excellent separation performance, easy regeneration, and remarkable reusability of MET‐Fe in both dry and humid conditions. With its high selectivity, large breakthrough capacity, and outstanding stability, MET‐Fe provides an ideal platform for industrial butene isomers separation.

Molecular Exclusion Separation of 1-Butene Isomers by a Robust Metal-Organic Framework under Humid Conditions.

Separating n-butene and i-butene by adsorption is an energy-efficient alternative, but designing porous adsorbents that distinguish the subtle differences between the isomers is extremely challenging. Currently, adsorbents that can sieve 1-butene isomers and are stable enough to withstand humid gas mixtures are largely unmet. Herein, we propose a robust ultramicroporous metal-organic framework (MET-Fe) that can separate 1-butene isomers through molecular exclusion. The pore aperture size (4.6 Å) precisely matches the kinetic diameters of the isomers, as verified by static and kinetic adsorption experiments and theoretical calculations. Furthermore, dynamic breakthrough experiments confirmed the excellent separation performance, easy regeneration, and remarkable reusability of MET-Fe in both dry and humid conditions. With its high selectivity, large breakthrough capacity, and outstanding stability, MET-Fe provides an ideal platform for industrial butene isomers separation.

Gas recirculation systems for RPC detectors: From LHC experiments to laboratory set-ups

The Resistive Plate Chamber (RPC) detectors are extensively used worldwide and at CERN LHC experiments thanks to their excellent time resolution and low cost. RPCs are often operated with a humidified gas mixture made of C2H2F4, SF6 and i-C4H10. Unfortunately, C2H2F4 and SF6 are greenhouse gases (GHGs) with a global warming potential (GWP) of 1430 and 22800 respectively and they are subject to a phase-down policy in Europe (EU F-gas regulation). It is therefore foreseeable that F-gases availability would be uncertain for the future and their price could raise possibly making gas detectors operation very costly. The reduction of GHG emissions is an objective of paramount importance for CERN and four different strategies have been identified to achieve it. One of these strategies is based on the use of gas recirculation systems. This solution is already implemented in all gas systems supplying gaseous mixtures to the CERN LHC detectors. These recirculation systems are complex and sophisticated apparatus for big detector volumes (tens to hundreds of m3) that extend from surface to underground cavern and they are controlled through an industrial Programmable Logic Controller (PLC). Their cost is considerable and therefore they are used for large detector apparatus. In order to cope with the increase of small experiments and detector facilities, the CERN gas team has developed two new portable gas recirculation systems at affordable cost. The first gas recirculation unit can be used for several detectors connected in series or parallel flushed with hundreds of liters per hour. It is controlled though a small PLC and it can regulate detector pressure at the level of the mbar. Some of these gas recirculation systems are already in use since several years at CERN GIF++ facility for CSC, GEM and RPC detectors. A second gas recirculation unit has been developed for laboratory purpose where one or two detectors are flushed with few liters per hour. In this case, the unit has to be very cheap and user-friendly in order to allow an easy operation from the final user. Both portable gas recirculation systems can be easily adapted for the different types of detector systems and set-ups thanks to their low price, flexibility and user-friendly operation. An overview of the LHC, medium and small gas recirculation systems will be given in this contribution.

Mixed matrix metal–organic framework membranes for efficient CO2/N2 separation under humid conditions

AbstractMixed matrix metal–organic framework (MOF) membranes show excellent application prospects in gas separation. However, their stability in various practical application scenarios is poor, especially under humid conditions. Herein, we encapsulated a hydrophobic ionic liquid (IL) into the cavity of MOFs, which effectively mitigated the competition between H2O and CO2 in humid gas mixtures, leading to stable and high‐performance gas separation. For this reason, the resulting membranes using polymer of intrinsic miroporosity‐1 (PIM‐1) as a polymer matrix show good CO2/N2 separation performance and long‐term test stability under humid environment. In particular, the 20 wt% IL‐UiO/PIM‐1 shows a high permeability of 13,778 Barrer and competitive CO2/N2 separation factor of ~35.2, transcending the latest upper bound. Besides, the according membrane module exhibits slightly decreased CO2 permeability and selectivity, promoting the application of self‐supporting membranes. This work provides a reliable strategy for the rational design of MOF‐based hybrid membranes under extreme conditions.

Non invasive ventilation and the high-flow nasal circuit

The purpose of this study is to discuss non-invasive ventilation and the High Flow Nasal Circuit (HFNC). The therapy is used by intensivists in Intensive Care Units – ICUs. It is a non-invasive breathing support modality that delivers heated and humidified gas mixtures to bedridden patients through a nasal cannula. The methodology used for the theme occurred in the online databases, Virtual Health Library (VHL) and Scientific Electronic Library Online (SCIELO). For greater reliability of the articles, a bibliographical survey of relevant studies was carried out, using keywords on the subject, and the selected articles had as criteria: clinical studies published in the last ten years. this new technique as a means of non-invasive ventilatory support, aims to provide the patient with greater comfort, improved oxygenation, reduced need for invasive mechanical ventilation and reduced reintubation rates. Because it is a new alternative, new studies must be carried out in the scientific academy.

Simultaneous Monitoring of Atmospheric CH4, N2O, and H2O Using a Single Gas Sensor Based on Mid-IR Quartz-Enhanced Photoacoustic Spectroscopy.

An optical sensor based on external-cavity quantum cascade laser (EC-QCL) was developed for simultaneous triple-species monitoring of CH4, N2O, and H2O vapor using off-beam quartz-enhanced photoacoustic spectroscopy (OB-QEPAS). The EC-QCL wavelength was scanned over three neighboring absorption lines of CH4 (1260.81 cm-1), N2O (1261.06 cm-1), and H2O vapor (1261.58 cm-1) by tuning the grating of the EC-QCL with a piezoelectric actuator. Molecular relaxation effects impacting the generation of the QEPAS signals resulting from light absorption by CH4 and N2O molecules were investigated in the mid-infrared region near 8 μm. A theoretical model was introduced for the mid-infrared region, including the beneficial influence of water vapor. An enhancement of the QEPAS signals by a factor of 3 for CH4 in air and of 20% for N2O in air was observed in humidified samples compared to that in dry samples. The QEPAS measurement was scaled by the calibrated reference spectrometers; detection limits of 98 ppbv for CH4, 12 ppbv for N2O, and 750 ppmv for H2O vapor were obtained with a 1σ signal-to-noise ratio (SNR = 1) in humidified gas mixtures. Real-time Kalman filtering was applied to improve the measurement precision by a factor of approximately 4 while keeping the same temporal resolution, leading to measurement precisions of 60 ppbv for CH4, 10 ppbv for N2O, and 0.07% for H2O in the measurements of 1.99 ppmv CH4 and 312 ppbv N2O humidified with 2.8% H2O vapor, with a 1 s lock-in amplifier time constant and an equivalent bandwidth of 0.1 Hz.

Effects of structure and chemistry on electrochemical transport properties of anion exchange membranes for separation of CO2

ABSTRACT The effects of structure, chemistry, and morphology of an anion exchange membrane (AEM) for separation of CO2 from a humidified gas mixture were characterized to determine the influence on the kinetics and transport properties of a membrane electrode assembly (MEA). Supported and unsupported membranes with thicknesses of 30 µm and 50 µm were used to determine through-plane resistance, ion transport capacity, and gas diffusion properties. The effects of membrane saturation on the membrane resistance was characterized by impedance measurements under conditions with varying relative humidity from 0% to 100%. Permeability measurements with varying CO2 concentration from 1% CO2 to 10% CO2 at temperatures of 25°C and 35°C determined changes in the membrane behavior, which could influence the performance of the CO2 separating MEA. This study characterized how AEM properties influence the behavior and performance of an electrochemical separating CO2 MEA suitable for high-humidity, low CO2 concentration environments. Pt and IrO2 electrodes were used evaluate the performance of unsupported and supported membranes within a MEA, characterized by electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and constant-current measurements to examine the CO2 electromigration.

Improving Catalytic Activity in the Electrochemical Separation of CO2 Using Membrane Electrode Assemblies

The direct electrochemically driven separation of CO2 from a humidified N2, O2, and CO2 gas mixture was conducted using an asymmetric membrane electrode assembly (MEA). The MEA was fabricated using a screen-printed ionomer bound Pt cathode, an anion exchange membrane (AEM), and ionomer bound IrO2 anode. Electrocatalyst materials were physically and chemically characterized prior to inclusion within the electrode. Electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV) measurements using a rotating disk electrode (RDE) were used to quantify the catalytic activity and determine the effects of the catalyst-to-ionomer ratio. Catalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface analysis, and (dynamic light scattering) DLS to evaluate catalyst structure, active surface area, and determine the particle size and bulk particle size distribution (PSD). The electrocatalyst layer of the electrodes were fabricated by screen printing a uniformly dispersed mixture of catalyst, dissolved anionic ionomer, and a solvent system onto an electrode supporting gas diffusion layer (GDL). Pt-IrO2 MEAs were fabricated and current-voltage relationships were determined using constant-current measurements over a range of applied current densities and flow rates. Baseline reaction kinetics for CO2 separation were established with a standard set of Pt-IrO2 MEAs.

Cs-RHO Goes from Worst to Best as Water Enhances Equilibrium CO2 Adsorption via Phase Change.

The strong affinity of water to zeolite adsorbents has made adsorption of CO2 from humid gas mixtures such as flue gas nearly impossible under equilibrated conditions. Here, in this manuscript, we describe a unique cooperative adsorption mechanism between H2O and Cs+ cations on Cs-RHO zeolite, which actually facilitates the equilibrium adsorption of CO2 under humid conditions. Our data demonstrate that, at a relative humidity of 5%, Cs-RHO adsorbs 3-fold higher amounts of CO2 relative to dry conditions, at a temperature of 30 °C and CO2 pressure of 1 bar. A comparative investigation of univalent cation-exchanged RHO zeolites with H+, Li+, Na+, K+, Rb+, and Cs+ shows an increase of equilibrium CO2 adsorption under humid versus dry conditions to be unique to Cs-RHO. In situ powder X-ray diffraction indicates the appearance of a new phase with Im3̅m symmetry after H2O saturation of Cs-RHO. A mixed-cation exchanged NaCs-RHO exhibits similar phase transitions after humid CO2 adsorption; however, we found no evidence of cooperativity between Cs+ and Na+ cations in adsorption, in single-component H2O and CO2 adsorption. We hypothesize based on previous Rietveld refinements of CO2 adsorption in Cs-RHO zeolite that the observed phase change is related to solvation of extra-framework Cs+ cations by H2O. In the case of Cs-RHO, molecular modeling results suggest that hydration of these cations favors their migration from an original D8R position to S8R sites. We posit that this movement enables a trapdoor mechanism by which CO2 can interact with Cs+ at S8R sites to access the α-cage.

The competitive adsorption mechanism of CO2, H2O and O2 on a solid amine adsorbent

Abstract To explore the effect of H2O and O2 on CO2 adsorption for branched polyethylenimine impregnated multi-walled carbon nanotubes (CNTs-PEI), the CO2 capacity and cyclic adsorption performance were measured under different gas mixtures (CO2/N2, CO2/H2O/N2, CO2/O2/N2, CO2/O2/H2O/N2). The competitive adsorption mechanisms among CO2, H2O and O2 were investigated by adsorption isotherms, adsorption energies and diffusion coefficient calculations, and in situ FTIR spectra of three gases adsorbed on CNT-PEI. The results showed that H2O had the highest adsorption energy and diffusion coefficient. This indicated the stronger interaction between H2O and CNT-PEI, resulting in the highest capacity of H2O. Furthermore, it also promoted amino groups reacting with CO2 at a mole ratio of 1:1, leading to the highest CO2 capacity under a humid gas mixture (CO2/H2O/N2) of up to approximately 5 mmol g−1. O2 had the lowest adsorption energy and diffusion coefficient, indicating that a small quantity of active sites was occupied by O2, which caused the less effect on CO2 capacity for the fresh adsorbent. However, it also reflected the lower desorption rate, which prolonged the contact time of amino groups with O2 and increased the probability of amino group oxidation. In situ FTIR spectra of O2 cyclically adsorbed on CNT-PEI proved the presence of amine oxide, which explained the continuous decrease in cyclic adsorption under a humid O2-containing gas mixture (CO2/O2/H2O/N2). CO2 molecules had moderate diffusion coefficient and adsorption energy, which proved excellent cyclic adsorption properties under dry gas mixture.

16 Embryo aggregation and adipose-derived mesenchymal donor cells in bovine somatic cell nuclear transfer

Somatic cell nuclear transfer (SCNT) is a powerful tool, but its efficiency remains low. The use of less differentiated donor cells or the embryo aggregation (EA) strategy improves the SCNT rates in several species. It remains unexplored whether the combined use of both strategies results in a synergistic effect that improves SCNT efficiency in bovine. To evaluate that, we assessed the optimal time of EA using IVF embryos (aim 1) and we evaluated whether the use of adipose-derived mesenchymal stem cells (ASC) as donor for SCNT together with EA improves the blastocyst rates and quality (aim 2). For aim 1, cumulus–oocyte complexes (COCs) were collected from slaughterhouse ovaries, invitro matured (TCM-199), fertilized (16×106 spermatozoa mL−1 for 5h) and cultured (synthetic oviductal fluid media in a humidified gas mixture at 39°C). After IVF, the zona pellucida was enzymatically removed and zona-free (ZF) embryos were cultured individually (1X) or 2 embryos placed together within a microwell (2X) (Day 0, n=70). This procedure was performed at Days 3, 4, 5, 6, or 7 (n=76, 78, 94, 96, 90, respectively) and blastocyst rate was assessed at Day 8. Contribution of both embryos to the 2X blastocyst was confirmed by staining Day 0 IVF embryos either with green or red Mitotracker (ThermoFisher Scientific) before EA. For aim 2, fibroblast (FB) and ASC cells were isolated from the skin and subcutaneous adipose tissue of the same adult animal, respectively. Cloned embryos were produced by ZF enucleation, fusion of one ASC or FB cell, and activation with 5μM ionomycin/6-(dimethylamino)purine (6DMAP). After activation, cloned embryos were aggregated (FB2X or ASC2X) or individually cultured (FB1X or ASC1X). Blastocyst rates were recorded at Day 7 of invitro culture. Three biological replicates were evaluated for each aim. Embryo developmental differences were determined using Fisher’s exact test. Relative expression of OCT4, SOX2, and KRT18 was measured by RTqPCR at the blastocyst stage and analysed by Kruskal–Wallis statistical test. Regarding aim 1, no differences for developmental rates were found for Day 0, 3, 4, and 5 groups (57%, 60%, 61.5%, 61%), but the blastocyst rate was only improved in Day 0 and Day 3 relative to their respective 1X controls (Day 0 2X 54.2% vs. Day 0 1X 25.5% and Day 3 2X 52.6% vs. Day 3 1X 25.3%). No aggregation occurred in Day 6 and Day 7 groups. All blastomeres were homogeneously distributed in the 2X blastocyst. Regarding aim 2, no effect of the donor cell was observed on the blastocyst rate (FB1X 26.8%, n=82; ASC1X 21.7%, n=198; FB2X 39.7%, n=126; ASC2X 33%, n=204), whereas EA improved the blastocyst rate of ASC-derived embryos (ASC1X 21.7% vs. ASC2X 33%). Overall, no synergistic effect of the use of both strategies was observed. Relative expression of KRT18 was significantly different between ASC1X and ASC2X embryos. Although OCT4 and SOX2 expression did not differ between groups, EA tended to bring the values closer to that of an IVF embryo. No effect of the donor cell was observed on the embryo relative expression. Our results suggest that EA at Day 0 improves the blastocyst rate in bovine SCNT and IVF embryos. EA of 2 ASC-derived embryos seemed to normalise the embryo quality and may improve post-implantation development.

20 Development and Oct4/Cdx2 gene expression of Puma concolor, Leopardus geoffroyi, and Panthera onca hybrid embryos produced using domestic cat oocytes

The development of assisted reproductive technologies (ARTs) in Felidae species has been proposed to guarantee the genetic viability of species that are on the verge of extinction. Investigation of sperm cryopreservation and IVF have been studied in several Felidae species, but the lack of viable homologous oocytes makes assessment of sperm fertilization capacity after cryopreservation difficult. We propose to evaluate the capability of Puma concolor (Pc), Leopardus geoffroyi (Lg), and Panthera onca (Po) cryopreserved sperm to induce domestic cat oocyte fertilization and subsequent pre-implantation embryo development. Additionally, we evaluated blastocyst quality by analysing the gene expression patterns of pluripotency (Oct4) and differentiation (Cdx2) related markers using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). After ovariectomy, domestic cat (Felis catus, Fc) cumulus–oocyte complexes were matured invitro at 38.5°C in a humidified atmosphere of 6.5% CO2 and 21% O2 for 22h. Cryopreserved sperm from Pc, Lg, and Po were used for heterologous IVF. The sperm was frozen using Tes-Tris–based diluent (TEST), and survival, sperm motility, and acrosome integrity were evaluated. The quality post-thaw was satisfactory. The survival was high, sperm motility (65%) did not decrease during incubation post-thaw, and sperm with intact acrosome was 62% for all species. Briefly, straws were thawed by exposing them to air for 10s and then immersing in a 37°C water bath for 30s. The contents of the straws were poured into prewarmed sterile 1.5-mL microtubes. The sperm suspension was diluted (1:3 vol/vol) by the slow (drop by drop) addition of a modified Tyrode’s solution (Pope et al. 2006 Methods Molec. Biol. 254, 227-244). For IVF, invitro matured oocytes (n=635) were co-incubated with 0.5×105 mL−1 motile spermatozoa at 38.5°C in a humidified atmosphere of 6.5% CO2 and 21% O2 for 18 to 20h. Presumptive zygotes were cultured invitro in 50-µL drops of modified Tyrode’s medium in a humidified gas mixture of 5% CO2, 5% O2, and 90% N2 at 38.5°C. Cleavage was determined 48h post-fertilization and blastocyst stage was evaluated at Day 8 and stored in RNA-Later at −20°C until RT-qPCR analysis. Data were analysed by Fisher’s exact test using GraphPad Prism 6.0 (GraphPad Inc.), and differences were considered significant at P<0.05. We observed significantly lower cleavage rates of Po hybrid (hPo) embryos compared with hPc, hLg, and control Fc embryos (41% vs. 57%, 68%, and 58%, respectively). Additionally, we found that the blastocyst rate was higher using Lg sperm compared with sperm of other groups [hLg (50%) vs. hPc (29%), hPo (21%), and Fc (27%)].

Determination of peppermint compounds in breath by needle trap micro-extraction coupled with gas chromatography–tandem mass spectrometry

Breath analysis is an alternative approach for disease diagnosis and for monitoring therapy. The lack of standardized procedures for collecting and analysing breath samples currently limits its use in clinical practice. In order to overcome this limitation, the ‘Peppermint Consortium’ was established within the breath community to carry out breath wash-out experiments and define reference values for a panel of compounds contained in the peppermint oil capsule. Here, we present a needle trap micro-extraction technique coupled with gas chromatography and tandem mass spectrometry for a rapid and accurate determination of alpha-pinene, beta-pinene, limonene, eucalyptol, menthofuran, menthone, menthol and menthyl acetate in mixed breath samples. Detection limits between 1 and 20 pptv were observed when 25 ml of a humidified standard gas mixture were loaded into a needle trap device at a flow rate of 10 ml min−1. Inter- and intra-day precisions were lower than 15%, thus confirming the reliability of the assay. Our procedure was used to analyse breath samples taken from a nominally healthy volunteer who was invited to swallow a 200 mg capsule of peppermint oil. Six samples were collected at various times within 6 h of ingestion. Analyte concentrations were not affected by the sampling mode (i.e. mixed vs. end-tidal fraction), whereas respiratory rate and exhalation flow rate values slightly influenced the concentration of the target compounds in breath samples.

Gas sensing behavior of ZnO toward H2 at temperatures below 300°C and its dependence on humidity and Pt-decoration

The sensing reaction mechanism of ZnO toward H2 was studied, and the effect of humidity and Pt decoration on the sensor performance was also investigated. Sputter-deposited ZnO thin films exhibit a distinct sensing response to H2 at temperatures above 150°C. An inverse V-shape response feature may develop upon the H2 exposure depending on the H2 concentration and the working temperature. The characteristic response feature results from a series of surface processes occurring on the ZnO surface, including ZnO reduction, Zn nanocluster growth, O2 adsorption on Zn nanoclusters and reoxidation of the nanoclusters. The sensor response to H2 is greatly deteriorated in humid ambient. However, the sensor shows a response enhancement toward humid H2 gas mixtures if the sensor surface is prepared to be initially free from H2O adspecies. This suggests that coexistence of hydrogen and water adspecies on the ZnO surface improves the sensor response to H2. When the ZnO thin film is decorated with Pt nanoparticles, the sensor performance is greatly improved both in dry and in humid environments. The improvement is proposed to result from hydrogen spillover from Pt nanoparticles to the ZnO support, which enhances the reaction rate of ZnO reduction by hydrogen adatoms.

High performance fluoride MFI membranes for efficient CO2/H2 separation

In the present work, ultra-thin MFI zeolite membranes prepared in fluoride media were evaluated for separation of equimolar CO2/H2 gas mixtures. Both dry and humid mixtures were evaluated. For dry gas mixtures, the membrane selectivity increased from 13 to 45 when the temperature decreased from 318 to 285 K, and CO2 flux was very high and almost constant at 4 mol m−2 s−1, corresponding to CO2 permeance of 100 × 10−7 mol m−2 s−1 Pa−1 (29851 GPU). For humid gas mixtures with a partial pressure of water of 3.5 kPa, the CO2 flux decreased from 3.27 to 0.10 mol m−2 s−1 when the temperature decreased from 316 to 288 K. The corresponding CO2 permeance decreased from 79 to 2.5 × 10−7 mol m−2 s−1 Pa−1 (from 23582 to 746 GPU). At the highest temperature 318 K, the CO2/H2 separation selectivity was slightly higher for the humid gas mixture. For the humid gas mixture, the CO2 flux increased from 3.27 to 3.76 mol m−2 s−1 at 318 K and from 0.52 to 0.90 mol m−2 s−1 at 296 K when the permeate pressure was reduced from atmospheric to vacuum, respectively. The separation selectivity of CO2/H2 was almost not affected by the permeate pressure. The results show that ultra-thin fluoride MFI zeolite membranes are promising candidates for separation of CO2 from dry or humid synthesis gas.

Water vapor condensation and collection by super-hydrophilic and super-hydrophobic VACNTs

Vertically Aligned Carbon Nanotubes (VACNTs) are well known for their easy production and great modification possibilities, such as oxidation and exfoliation. Some functionalization methods can quickly change carbon nanotubes wettabillity from super-hydrophobic to super-hydrophilic. These last ones have great potential for fog harvesting or other humid gas mixture harvesting. In this work, we used these carbon nanotubes features to develop a super-hydrophobic/super-hydrophilic patterned surface to collect water droplets from humid air. This structure has been designed to biomimic the Stenocara beetle one. In this work we show that water condensation happens on self-cleaning super-hydrophobic surface and then the droplets are pumped by the super-hydrophilic surface. The super-hydrophobic surface was made by deposition of polyethylene on pristine VACNTs/steel screen. The super-hydrophilic surface was fabricated by deposition of functionalized VACNTs on carbon fiber felt. We performed the water collection measurement into a homemade chamber with fog-like humidity control. The best result reached was about 30 (L/m2)/h under controlled conditions.

A Pilot Study of Inhaled CO Therapy in Neonatal Hypoxia-Ischemia: Carboxyhemoglobin Concentrations and Brain Volumes.

Objective: The objective of this pilot study was to start evaluating the efficacy and the safety (i.e., carboxyhemoglobin concentration of carbon monoxide (CO)) as a putative neuroprotective therapy in neonates.Study Design: Neonatal C57BL/6 mice were exposed to CO at a concentration of either 200 or 250 ppm for a period of 1 h. The pups were then sacrificed at 0, 10, 20, 60, 120, 180, and 240 min after exposure to either concentration of CO, and blood was collected for analysis of carboxyhemoglobin. Following the safety study, 7-day-old pups underwent a unilateral carotid ligation. After recovery, the pups were exposed to a humidified gas mixture of 8% oxygen and 92% nitrogen for 20 min in a hypoxia chamber. One hour after the hypoxia exposure, the pups were randomized to one of two groups: air (HI+A) or carbon monoxide (HI+CO). An inhaled dose of 250 ppm of CO was administered to the pups for 1 h per day for a period of 3 days. At 7 days post-injury, the pups were sacrificed and the brains analyzed for cortical and hippocampal volumes.Results: CO exposure at 200 and 250 ppm produced a peak carboxyhemoglobin concentration of 21.52 ± 1.18% and 27.55 ± 3.58%, respectively. The carboxyhemoglobin concentrations decreased rapidly, reaching control concentrations by 60 min post exposure. At 14 days of age (7 days post injury), the HI+CO (treated with 1 h per day of 250 ppm of CO for 3 days post injury) had significant preservation of the ratio of ipsilateral to contralateral cortex (median 1.07, 25% 0.97, 75% 1.23, n = 10) compared the HI+A group (p < 0.05).Conclusion: CO exposure of 250 ppm did not reach carboxyhemoglobin concentrations which would induce acute neurologic abnormalities and was effective in preserving cortical volumes following hypoxic-ischemic injury.

In-vitro model of the Penumbra: closed-loop optogenetic stimulation to improve cell survival.

In-vitro model of the Penumbra: closed-loop optogenetic stimulation to improve cell survival.