The estimation of soil wet bulk density (ρ_n) and dry bulk density (ρ_b) using the novel digital electromechanical system (DES) has provided information about important parameters for the assessment of soil quality and health with a direct application for agronomists. The evaluation of the DES performance is particularly appropriate for different tillage methods, mulching systems, and fertilizers used to increase soil fertility and productivity, but currently, there is a lack of information, particularly in the arid areas in underdeveloped countries. Therefore, the main aim of this study was the application of a novel digital electromechanical system (DES) to evaluate bulk density, wet (ρ_n) and dry (ρ_b), under different soil treatments according to the variations in thermal efficiencies (η_th), microwave penetration depths (M_DP), and specific energy consumption (Q_con) in an experimental area close to Baghdad (Iraq). The experimental design consisted of 72 plots, each 4 m². The agronomic practices included two different tillage systems (disc plough followed by a spring disk and mouldboard plough followed by a spring disk) and twelve treatments involving mulching plastic sheeting combined with fertilizers, to determine their effect on the measured soil ρ_n and ρ_b and the DES performance in different soils. The results indicated that soil ρ_n and ρ_b varied significantly with both the tillage systems and the mulching systems. As expected, the soil ρn and ρb, M_DP, and Q_con increased with an increase in the soil depth. Moreover, the tillage, soil mulching, and soil depth value significantly affected η_th and Q_con. A strong relationship was identified between the soil tillage and M_DP for different soil treatments, leading to the changes in soil ρ_b and the soil dielectric constant (ε’).

In this study, the effect of gas flow field design on fuel cell performance was investigated numerically. Polymer electrolyte membrane fuel cells were used. The fuel cell used in this study has a Z-shaped flow field design. Nineteen different flow field models were designed and tested in this study, including Scheme 1 inf, Scheme 2 inf, Scheme 3 inf, Scheme ins_1, Scheme ins_2, Scheme ins_3, Scheme 1S, Scheme 2S, Scheme 3S, Scheme 1U, Scheme 2U, Scheme 3U, Scheme 1Z, Scheme 2Z, Scheme 3Z, Scheme W, Scheme W with one Pypass, Scheme W with two Pypass, and Scheme sph). Numerical simulations were performed using COMSOL Multiphysics 6.1 software to make comparisons between all flow channels proposed in the current study in terms of pressure loss distributions on both sides of the fuel cell (anode and cathode), velocity distributions on the anode and cathode, also hydrogen and oxygen concentration distributions, water on the anode and cathode side, current density distributions on the membrane. Comparing the results of the designs showed the superiority of the two-tunnel W scheme over all other studied designs. From the simulation results, it was noted that the modified serpentine single flow field design W is good in terms of distribution Compression and management of reactants and products compared to other channels in the same area.