Modeling of Hydrogen Absorption/Desorption in a Metal Hydride Bed Reactor — A Theoretical Study

Hydrogen has been considered as an alternative source of fuel to the fossil fuel in future, most especially, for mobile applications. However, a requirement is the safe, efficient and compact on- board storage of hydrogen. Reversible storage in metal hydride is promising, but adequate knowledge of materials system fulfills all requirements regarding hydrogen content is a major drawback, release temperature, and reversibility simultaneously. Hydrogen absorption- desorption in a metal hydride bed reactor can be modeled using different software such as FLUENT, CFD-ACE, and COMSOL Multiphysics. This book chapter will focus on the use of software COMSOL Multiphysics to simulate the diffusion and heating of hydrogen and metal hydride powder in both radial and axial directions. The model consists of system of partial differential equations (PDE) describing two-dimensional heat and mass transfer of hydrogen in a porous matrix. The influence of the operating parameters Temperature, Pressure, Concentration, Permeability and Thermal Conductivity on the rate of absorption-desorption of hydrogen in metal hydride will be fully discussed. The simulation results obtained could be applied to the on - board hydrogen storage technology, in particular for the hydrogen supply of a fuel cell for powering of a hydrogen fuel cell vehicle

Evaluation of the synergistic properties of 4-hydroxy-3-methoxybenzaldehyde and 1, 4-diaminobenzene on the electrochemical corrosion behaviour of mild steel in dilute acid solutions

The electrochemical corrosion behaviour of the synergistic effect of 4-hydroxy-3-methoxybenzaldehyde and 1, 4-diaminobenzene on mild steel in dilute sulphuric and hydrochloric acid solution (1M concentration) with 1.5% recrystallized sodium chloride evaluated with weight loss analysis, potentiodynamic polarization test and optical microscopy. Statistical analysis of the results was done with Two-way ANOVA to assess their statistical significance of the experimental variables on inhibition efficiency values. Results show the combined organic derivatives performed effectively in both acids with average inhibition efficiency values above 85%. Observations from optical microscopy images further confirm the results of experimental data. Statistical derivations reveal the overwhelming significance of exposure time only inhibition efficiency values in both acids

Occurrence of arbuscular mycorrhizal fungi spores in soils of some legumes and their response to varying concentrations of phosphorus application

A potted experiment arranged in a 5 × 3 factorial in a randomized complete block design was undertaken to investigate the occurrence of arbuscular mycorrhizal fungi (AMF) in the soil of five leguminous plants: Cajanus cajan (L.) Huth, Centrosema pascuorum Martius ex Benth, Crotalaria ochroleuca G. Don, Lablab purpureus (L.) Sweet and Mucuna pruriens (L.) DC. The effects of varying phosphorus concentrations (P0) (0 kg/ha of single superphosphate), P1 (100 kg/ha of single superphosphate) and P2 (200 kg/ha of single superphosphate) on the population of AMF spores under these legumes were also carried out. The AMF spores in soil samples were extracted at 19 weeks after planting, using the wet sieving and decanting method, and enumerated with the aid of a stereoscopic microscope. Spores of different species of genera Glomus and Gigaspora were encountered in the soils of the five leguminous plants. Spores of Glomus species predominated while the spores of Gigaspora species were found in lower numbers. The total AMF population was significantly affected by legume species (p ≤ 0.05). The total AMF spore counts were higher in the soils of Mucuna pruriens and Crotolaria ochroleuca (p ≤ 0.05). The populations of Glomus mossae in soils decreased with increasing level of applied phosphorus (p ≤ 0.05). A positive correlation was recorded between the total AMF spores, the predominant AMF spores and soil pH, while the organic matter content and the available phosphorus were negatively correlated with both the total AM spores and the predominant AMF spores