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Zero-gap liquid alkaline water electrolyzers have great potential for hydrogen production. In order to enhance their actual performance, one of the key components to investigate is the anionic exchange membrane that allows the conduction of anions between the electrodes. This paper reports the preparation and characterization of membranes composed of a polybenzimidazole, either poly(2,5-benzimidazole) (ABPBI) or poly[2-2′-(m-phenylene)-5-5′-bibenzimidazole] (PBI), crosslinked with different ratios of poly(vinylbenzyl chloride) (PVBC), forming thermally stable and homogeneous films. Quaternization of these films with 1,4-diazabicyclo (2.2.2) octane (DABCO) followed by immersion in an alkaline solution lead to the introduction of quaternary ammonium groups and hydroxide anions respectively. Adequate thermal stability is observed in the temperature range of application (below 100 °C). Measurements of KOH and water and related swelling reflect the higher absorption capacity of ABPBI based membranes relative to PBI based ones. ABPBI-c-PVBC/OH 1:2 membranes at 50 °C are characterized by high ionic conductivity values (48 mS cm−1), reaching 380 mA cm−2 at cell voltage 1.98 V. In conclusion, we consider that these membranes are competitive candidates as anion exchange membranes for zero-gap alkaline water electrolyzers, and can be further enhanced to reach the performance of state of the art AEM’s.

We developed an innovative polymer blend system composed of polyvinyl alcohol (PVA) and polybenzimidazole as an anionic membrane for application to zero gap alkaline electrolysers. The challenge was to combine PVA with either poly[2-2′-(m-phenylene)-5-5′-bibenzimidazole] (PBI) or poly (2,5-benzimidazole) (ABPBI) to complement these neutral polymers, which must be doped to conduct, with hydroxyl groups that benefit the OH− transport mechanism. We studied PVA-PBI and PVA-ABPBI membranes with compositions varying between 2:1 and 8:1, with 4:1 being best ratio. PVA is crosslinked inside PVA-PBI 4:1 and PVA-ABPBI 4:1 membranes with glutaraldehyde (GA) by immersion in a reaction solution with different GA contents ranging from 0.5 vol% to 50 vol% to enhance the stability of the membranes. The chemical stability in a KOH environment, thermal and mechanical properties, surface morphology, swelling, water/KOH sorption, and conductivity of the linear alkali-doped (L-PVA-PBI, L-PVA-ABPBI) and crosslinked (C-PVA-PBI, C-PVA-ABPBI) membranes were analysed. The best results were observed for the C-PVA-ABPBI 4:1 membrane crosslinked in 0.5 vol% GA, which exhibited specific conductivities at 90 °C of 50 mS cm−1 and 90 mS cm−1 when doped using 15 wt% and 30 wt% KOH, respectively. In short-term electrolysis tests performed with circulated 15 wt% KOH at 50 °C, this membrane exhibited a current density that was twice that of the commercial porous Zirfon® diaphragm (i.e., 300 mA cm−2 and 140 mA cm−2, respectively) at a cell voltage of 2.0 V. The performance achieved with the C-PVA-ABPBI membrane in a 15 wt% KOH electrolyte at 70 °C was good (i.e., 360 mA cm−2 at a cell voltage of 1.9 V).

An easy treatment based in carbon layer deposition into aluminium alloys is presented to enhance the performance of Al-air primary batteries with neutral pH electrolyte. The jellification of aluminate in the anode surface is described and avoided by the carbon covering. Treated commercial Al alloys namely Al1085 and Al7475 are tested as anodes achieving specific capacities above 1.2 Ah g−1 vs 0.5 Ah g−1 without carbon covering. The influence of the binder proportion in the treatment as well as different carbonaceous materials, Carbon Black, Graphene and Pyrolytic Graphite are evaluated as candidates for the covering. Current densities of 1–10 mA cm−2 are measured and the influence of the alloy explored. A final battery design of 4 cells in series is presented for discharges with a voltage plateau of 2 V and 1 Wh g−1 energy density.

We consider a set of M images, whose pixel intensities at a common point can be treated as the components of a M-dimensional vector. We are interested in the estimation of the modulus of such a vector associated to a compact source. For instance, the detection/estimation of the polarized signal of compact sources immersed in a noisy background is relevant in some fields like astrophysics. We develop two different techniques, one based on the maximum likelihood estimator (MLE) applied to the modulus distribution, the modulus filter (ModF) and other based on prefiltering the components before fusion, the filtered fusion (FF), to deal with this problem. We present both methods in the general case of M images and apply them to the particular case of three images (linear plus circular polarization). Numerical simulations have been performed to test these filters considering polarized compact sources immersed in stationary noise. The FF performs better than the ModF in terms of errors in the estimated amplitude and position of the source, especially in the low signal-to-noise case. We also compare both methods with the direct application of a matched filter (MF) on the polarization data. This last technique is clearly outperformed by the new methods.

On the present work the objective is to manufacture a AA2014+10 vol-% Intermetallic (NbAl3 or FeAl2 ) metal matrix composites. Since Powder Metallurgy route was chosen, the powder mixtures of metallic powders which forms AA2014 alloy and intermetallic powders were obtained by mechanical alloying. Powder mixtures were cold die pressing and green samples were hot extruded. As result of this intermetallic addition, mechanical properties of AA2014 alloy are improved and a tensile strength of 516 MPa on AA2014+NbAl3 and 465MPa on AA2014+FeAl2 within an elongation close to 2% on both metal matrix composite materials are reached.El objeto del presente trabajo es la obtención de los materiales compuestos AA2014 +10 vol-% NbAl3 o FeAl2. Para ello se realizó la mezcla inicial de los polvos metálicos que constituyen la aleación AA2014 y de los polvos de estos intermetálicos seguido de su aleación. Las mezclas obtenidas se compactaron en frío y los compactos en verde se extruyeron en caliente. Como resultado de la adición de los intermetálicos se mejoran las propiedades mecánicas de la aleación AA2014, alcanzándose resistencias a tracción de 516 MPa para el AA2014+NbAl3 y de 465MPa para el AA2014+FeAl2, con un alargamiento próximo al 2.0% en ambos materiales compuestos de matriz metálica.