## 3 Results and Discussion
Also, the rate of decrease in pressure of the reservoir shows that the time required to absorb an identical amount of hydrogen in each case is decreased by implementing magnetic fields. Thus, applying magnetic fields enhances hydrogen absorption time in a LaNi\({}_{5}\) bed. It is postulated that the variation in equilibrium pressure and temperature is because of the decreased permeability and increased heat transfer area in the system, due to the compaction of particles when magnets are present. The mass of absorbed hydrogen under each magnet is presented in Table 3. The mass is calculated by measuring the volume of absorbed hydrogen under normal conditions (\(T=293\) K & P = 101 kPa) and using the density of hydrogen under normal conditions (\(\rho=0.089\) kg/m\({}^{3}\)). The driving potential for the hydriding reaction is the difference between the metal hydride tank pressure and equilibrium pressure; the larger this difference is, the faster is the reaction rate. The rate can be increased by either increasing the pressure or reducing the metal hydride temperature. If sufficient cooling is provided during a small pressure increment during the pressure ramp, the metal hydride temperature will be maintained below the equilibrium temperature, and the reaction continues as the pressure increases by a second increment. However, if the cooling is insufficient, the metal hydride temperature reaches the equilibrium temperature and the reaction stalls. From the calculated absorbed hydrogen for each experiment, it is evident that magnetism increases the amount of hydrogen which can be absorbed in lanthanum nickel. The hydrogen absorption amount (practical absorption capacity) should not be confused with theoretical absorption capacity, which is 1.5% for LaNi\({}_{5}\). The information presented in Table 3 is an indication of practical absorption capacity which can change by the change in the equilibrium condition of the chemical hydrogen absorption/desorption reactions. A change in the amount of absorbed hydrogen does not mean that there is a change to the theoretical hydrogen absorption capacity of the substance. Thus far, the positive effect of magnetism on thermal conduction and hydrogen absorption capacity in LaNi\({}_{5}\) was tested. A series of experiments were performed to identify whether improved hydrogenation properties are because of the chemical reaction or because of the enhanced heat transfer rates. In these experiments, a hydriding process was initiated without magnetism on the setup. When hydriding reaches equilibrium, a magnet (magnet 2) is placed at the bottom of the reactor which causes the sudden temperature fluctuation shown in Figure 8. The temperature slope changes by adding the magnet (as presented in Figure 8), which supports the previous conclusion of changed equilibrium temperature and pressure in a magnetic field. However, as there is no significant change in the temperature pattern, no extra hydrogenation occurs by adding a magnet. Meanwhile, as illustrated in Figure 9, pressure does not have any changed slope when the magnetic field is applied. Consequently, no more hydrogen absorption occurs at this stage. From this experiment, it is concluded that the chemical reaction does not change by magnetism and the enhanced hydrogenation properties of the hydride are because of the enhanced heat transfer rate. \begin{table}
\begin{tabular}{c c} \hline \hline
**Boundary Condition** & \(\Delta m\) **(gr)** \\ \hline No magnet & 0.619 \\ Magnet 1 & 0.818 \\ Magnet 2 & 0.909 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Mass of absorbed hydrogen under different magnetic conditions. Figure 7: Pressure measurement inside reactor (**Top**) and reservoir (**Bottom**) during hydrogenation under different magnetic conditions. Figure 8: Temperature measurement inside reactor (**Top**) and the tank wall (**Bottom**) during hydrogenation.