Voedingsoplossingen voor de teelt van Cymbidium in substraat

In deze brochure zijn voedingsoplossingen opgenomen voor de teelt van Cymbidium in substraat. Bij deze voedingsoplossingen is onderscheid gemaakt tussen de teelt in oasisgranulaat en steenwolgranulaat. Met enige aanpassing zijn de schema's ook bruikbaar voor de teelt in turf. De schema's voor oasisgranulaat gelden mogelijk ook voor andere kunstmatig gefabriceerde schuime

Deuterium retention and removal in liquid lithium determined by in-situ NRA in Magnum-PSI

In this work, Li-filled 3D-printed porous tungsten samples were exposed to deuterium (D) plasma in Magnum-PSI with a wide ion flux from 4×1022 to 1.5×1024 m-2s-1 and with a corresponding wide temperature range from below Li melting point (180.5 °C) to above Li deuteride (LiD) melting point (~ 690 °C). The formation, decomposition and melting of LiD have been directly observed in the experiment via infra-red thermometry and visually post-mortem while still in vacuo, and correlated to the D retained content. The LiD formation was characterized by a solid precipitate layer formed on the surface with high emissivity (0.6 ~ 0.9) characterized by a blue or dark blue colour after exposure. The melting of Li-LiD layer was found to occur close to the temperature predicted by Li-LiD phase diagram. In-situ Nuclear Reaction Analysis (NRA) was applied to perform the measurement of D retained in Li samples immediately after exposure without breaking the vacuum. D depth profiles were determined by NRA, in which the highest D concentration (15 – 45 at.%) was found in the top several micrometers and decreases with depth to low levels (<5%) within 5-30 micrometers. No pure LiD layer was found on the sample surfaces, however a D concentration close to 50 at.% was observed on a Li-D co-deposited layer on the clamping ring in some cases. The experiments also indicate that the D retained increases with increasing temperature until ~ 500 °C. At temperatures beyond ~ 500 °C the dissociation of LiD starts to dominate and the deuterium retention started to decrease. Overall, D retained fraction for all cases was found to be below ~ 2 %, which is significantly different from literatures where full uptake has been suggested. A 1D reaction-diffusion (RD) model based on D diffusion and chemical reactions with Li has been built. D depth profiles from the RD modelling can roughly match that from NRA measurement and a low D retained fraction below ~ 2 % was also indicated by the model. The model can also help explain the relationship between D retained and the surface temperature and fluence. After D plasma exposure, either helium or H plasma was utilized to remove the retained D in Li and both were proved to be effective and the removal efficiency can be as high as 96 % above 420 °C

Deuterium retention and removal in liquid lithium determined by in-situ NRA in Magnum-PSI

In this work, Li-filled 3D-printed porous tungsten samples were exposed to deuterium (D) plasma in Magnum-PSI with a wide ion flux from 4×1022 to 1.5×1024 m-2s-1 and with a corresponding wide temperature range from below Li melting point (180.5 °C) to above Li deuteride (LiD) melting point (~ 690 °C). The formation, decomposition and melting of LiD have been directly observed in the experiment via infra-red thermometry and visually post-mortem while still in vacuo, and correlated to the D retained content. The LiD formation was characterized by a solid precipitate layer formed on the surface with high emissivity (0.6 ~ 0.9) characterized by a blue or dark blue colour after exposure. The melting of Li-LiD layer was found to occur close to the temperature predicted by Li-LiD phase diagram. In-situ Nuclear Reaction Analysis (NRA) was applied to perform the measurement of D retained in Li samples immediately after exposure without breaking the vacuum. D depth profiles were determined by NRA, in which the highest D concentration (15 – 45 at.%) was found in the top several micrometers and decreases with depth to low levels

In-situ LIBS and NRA deuterium retention study in porous W-O and compact W coatings loaded by Magnum-PSI

The purpose of this study is to investigate the applicability of in-situ laser induced breakdown spectroscopy (LIBS) for deuterium retention measurements in tungsten coatings with different morphology and oxygen content. These were exposed to a Gaussian beam of deuterium plasma in the Magnum-PSI linear plasma device. The deuterium line intensities determined by LIBS were compared with the deuterium content measured by nuclear reaction analysis (NRA). Both LIBS and NRA results showed that higher deuterium retention was achieved in the coating region corresponding to the periphery of the plasma beam. This decreasing deuterium retention in the central region can be attributed to higher surface temperature. At the same time, the deuterium retention in different coating types assessed by LIBS D intensity was markedly different from the retention determined by NRA. Porous W-O coating with high oxygen content had the highest deuterium retention according to NRA while D intensity obtained by LIBS was an order of magnitude smaller when compared with other coatings. The deuterium retention in compact W coating and thick W coating was almost the same and LIBS D intensities were also comparable for these coatings. The results demonstrate the LIBS applicability and its limits in different coating types.</p

Overpotential analysis of alkaline and acidic alcohol electrolysers and optimized membrane-electrode assemblies

Alcohol electrolysis using polymeric membrane electrolytes is a promising route for storing excess renewable energy in hydrogen, alternative to the thermodynamically limited water electrolysis. By properly choosing the ionic agent (i.e. H+ or OH) and the catalyst support, and by tuning the catalyst structure, we developed membrane-electrode-assemblies which are suitable for cost-effective and efficient alcohol electrolysis. Novel porous electrodes were prepared by Atomic Layer Deposition (ALD) of Pt on a TiO2-Ti web of microfibers and were interfaced to polymeric membranes with either H+ or OH conductivity. Our results suggest that alcohol electrolysis is more efficient using OH conducting membranes under appropriate operation conditions (high pH in anolyte solution). ALD enables better catalyst utilization while it appears that the TiO2-Ti substrate is an ideal alternative to the conventional carbon-based diffusion layers, due to its open structure. Overall, by using our developmental anodes instead of commercial porous electrodes, the performance of the alcohol electrolyser (normalized per mass of Pt) can be increased up to ~30 times

Overpotential analysis of alkaline and acidic alcohol electrolysers and optimized membrane-electrode assemblies

Alcohol electrolysis using polymeric membrane electrolytes is a promising route for storing excess renewable energy in hydrogen, alternative to the thermodynamically limited water electrolysis. By properly choosing the ionic agent (i.e. H+ or OH) and the catalyst support, and by tuning the catalyst structure, we developed membrane-electrode-assemblies which are suitable for cost-effective and efficient alcohol electrolysis. Novel porous electrodes were prepared by Atomic Layer Deposition (ALD) of Pt on a TiO2-Ti web of microfibers and were interfaced to polymeric membranes with either H+ or OH conductivity. Our results suggest that alcohol electrolysis is more efficient using OH conducting membranes under appropriate operation conditions (high pH in anolyte solution). ALD enables better catalyst utilization while it appears that the TiO2-Ti substrate is an ideal alternative to the conventional carbon-based diffusion layers, due to its open structure. Overall, by using our developmental anodes instead of commercial porous electrodes, the performance of the alcohol electrolyser (normalized per mass of Pt) can be increased up to ~30 times