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Urban hydrologyAppreciating the dynamics of the hydrological cycle in the urban domain requires consideration of both the natural water cycle and the manmade elements which interact with it, such as those for storage and conveyance (Barbosa, Fernandes & David 2012). Not only does this lead to more complex pathways through the cycle due to the increased number of elements involved, but creates challenges for data collection as often these manmade elements are owned by private companies, leading to uncertainties and difficulty in accessing information on channel (pipe) size and locations (Noh et al. 2016).In addition, the processes and storages of the natural water cycle are also altered in the urban domain, with potential for some being reduced (see Figure 1). For example, the increased impermeable surface area relative to an undeveloped parcel leads to reduced infiltration and evapotranspiration, with a resultant increase in surface runoff (Anim et al. 2019). Reduced infiltration into permeable, undeveloped land also leads to reduced groundwater level and less resilience of the land to prolonged dry periods.Management in the urban form usually results in attempts to control where the water is located, too, through the channelling of water into drains and pipes. This is then conveyed out of the populated area. Consequently, when the inflow is greater than the outflow (during intense and/ or persistent rainfall), problems are exacerbated as there is little storage capacity and water collects in these areas.As a result, the spatial and temporal scale of the subprocesses in the hydrological cycle are much smaller in

Nuclear alinement of the isotopes 149 Pm and 151 Pm has been obtained in the ethyl sulphate and double nitrate lattices by the low-temperature alinement method. The anisotropic γ -ray angular distributions were used to detect this alinement. The results suggest that in the double-nitrate lattice the lowest ionic state of Pm 3+ is a singlet and that alinement arises through a ‘pseudo-quadrupole’ mechanism. Beta and γ -spectroscopy measurementsshow that the 285 keV γ -ray in the decay of 149 Pm is associated with a weak (1.8 ± 0.3 %) β -group of maximum energy 0.77 ± 0.05 MeV. The alinement measurements are consistent with this 285 keV γ -ray being principally M 1 with the spin of the excited state being 5/2 or 9/2.

Cobalt-55 has been alined in a crystal of nickel, zinc fluosilicate which was magnetically cooled to 0.004°K, and the anisotropy of the 0.935 and 1.41 MeV radiations studied as a function of temperature. On the assumption that the spin of 55 Co is 7/2, the spins of the 0, 0.935 and 1.41 MeV levels in 55 Fe are 3/2, 5/2 and 7/2 respectively with presumably odd parity; the 0.935MeV γ -ray is a dipole-quadrupole mixture with δ = + 0.37 ± 0.04. The magnetic moment of 55 Co is 4.3 ± 0.3n.m. and the Fermi admixture in the β -transition to the 1.41 MeV level of 55 Fe is less than 10% . The crystals used consisted of an inactive core on to which a layer several millimetres thick and containing the cobalt activity ( 55 Co, 56 Co, 58 Co or 60 Co), was grown. Data concerning the effect of the nickel concentration in the active layer on the cooling properties of such crystals are presented. The rapidity and ease with which these crystals may be grown should make the technique applicable to isotopes with half-lives as short as 10h. New data on the 58 Co alinement indicates that a Fermi admixture of 1 ± 1 % is associated with the β -transition.