4. Concluding remarks

temperature deviates from the room temperature and the possible reason of this deviation is the

The regular regime method is useful to determine the content-dependent diffusion coefficient for systems in which the relation among moisture diffusivity and moisture content are lineal and the last one decreasing below the critical moisture concentration or also for situations where the drying rate is dominated by mass transfer inside the drying specimen [57]. Under this theory, the drying curves show an induction period in which the drying rate is conditioned by the moisture distribution at the beginning of the drying process and a regular regime period in which the drying rate is not correlated and thereby of the moisture distribution at the beginning of the process. The establishment of the moisture range at which the regular regime occurs during the isothermal drying is the condition to apply this method, particularly for a given material and conditions, the drying curves will converge in a regular regime curve, even

increasing importance on thermal-buoyancy convection at higher temperatures [54].

for different moisture contents in a single curve named the regular regime curve [49].

materials against lipid oxidation [49].

100 Current Perspective to Predict Actual Evapotranspiration

thin porous layers.

3.4.7. Natural convection in cavities

The objective of the work of [49] was to develop a method for quantitatively calculating the effective moisture diffusivity of isothermally dried biopolymer drops and to acquire activation energy to be used as a discriminating parameter for selecting effective wall materials against lipid oxidation. The biopolymer´s effective moisture diffusivity was dependent on moisture content and temperature. Therefore, air temperatures must be lower than 80C for an appropriate analysis of the water diffusion mechanism using the regular regime methodology. Also, the activation energy provides a quantitative measurement for selecting potential good wall

In other approach, the interactions of droplets during its deposition on porous material for the agglomeration of particles by spray-fluidized process were studied by [55]. In this work, the penetration of liquid into the porous layer was assumed to be governed by Darcy's law. In reference [48] the molecular kinetic theory was used to model the droplet spreading, and Darcy's law to describe the one-dimensional liquid penetration into the substrate. Particularly, this approach is of interest for applications of formulation of EPNs because the elemental principle of the methods of formation of GBs is to deposit droplets of aqueous suspension containing EPNs over a layer of a mixture of material (carrier and adjuvants) and then the penetration of the liquid carrier happened [5, 9]. After that, the materials are mixed and compacted in different ways (i.e. agitation, eccentric rotational motion and compaction by rolling, among others). These are reasons to optimize the capillary penetration of aqueous suspension into the porous layer; the initial moisture content and moisture evaporation are critical factors in the design of granules for storage and transport of EPNs for biological applications [3, 50]. Following this approach, in [56] was developed a method to quantitatively describe the evaporation effect on radial capillary penetration of liquids in

The case study of Prakash et al. [32] is moisture migration in a rectangular cavity (2 m in height and 1 m in diameter) with half the cavity filled with silica gel and their paper presents a According to this review focus, it has been found that the evaporation theory from porous media is well developed, and is affected by temperature, atmospheric pressure, humidity, water quality, topology, size and organization of particles and pores, fissures, type of elaboration process and shape of surface among others in an interdependent form. Therefore, as a design object, GBs are the porous granular structure whose key evaporative processes are subject to multiple extra- and intra-structure factors that affect the way of water removal and even other physical, chemical and mechanical processes in a complex way. For the above, considering all the phenomena in the design process of GBs without theoretical support and mathematical tools for the analysis of the transport processes limits the design of optimized solutions. Nevertheless, it is reasonable to think that some improvements can be achieved on this topic because the optimization methods (as the topology optimization procedure used to design heterogeneous materials and stochastic optimization methods employed to reconstruct or construct such microstructures gave limited but targeted structural information) provide a systematic means of designing of microstructures with tailored properties for a specific application. Also, mechanistic and correlative models of evaporation are available to analyse the desiccation of GBs, i.e. describe most of the moisture evaporation process from GBs that could be useful to estimate the time required to reach optimum moisture or conditions to achieve the adequate drying rate of different EPNs. The theory of drying processes in two stages for porous materials with high moisture content seems to be a starting point to explore further the moisture evaporation from GBs at different scales. We suggest that considering the complex physical, chemical and mechanical processes carried out in soil to supply the necessary conditions (i.e. oxygen, humidity, temperature, mechanical strength) for the nematodes to achieve their survival and persistence in soil, and the actual development of the research area, new characteristics should be accomplished in the formulates to mimic the anhydrobiosis induction processes and maintain the stationary state of quiescence for the successful longterm storage of viable EPNs, as if the formulates were a microstructured porous reservoir. This also implies previous work to improve the EPNs biology fitness, e.g. on the pre-acclimatization of IJs before and after formulation. For which, the use of desiccators' technology to gradual drying of large amounts of IJs is a potential topic not commonly explored in the formulation process of EPNs.

### Acknowledgements

This work was supported by the SIP project number 20170139. We thank to the Instituto Politécnico Nacional (IPN) and to the Comisión de Operación y Fomento de Actividades Académicas (COFAA) from IPN.
