A Novel Analytical Model of Solute Transport in an Aquifer-Aquitard System with Mixing Processes in the Reservoirs

Analytical models have been widely used to aid understanding the physical and chemical processes of tracer (or chemicals) in an aquifer-aquitard system in the laboratory-controlled experiment, when the observation data is few or not available during the experiment. When injecting tracer into (or extracting them from) the aquifer-aquitard system during experiments, the pre-inlet and after-outlet reservoirs are indispensable. However, the concentration variation in the reservoirs was not treated properly in previous analytical models, resulting in poor performance in interpreting experimental data. In this study, new mathematical models describing the concentration variation in the pre-inlet and the after-outlet reservoirs are proposed, and they are integrated into the novel analytical model. The novel analytical model is developed under the mobile-immobile (MIM) framework in the aquifer-aquitard system, considering the longitudinal and vertical dispersion, the advection, and the first-order chemical reaction in both aquifer and aquitard. A finite-difference solution is developed and the experimental data are employed to test the new analytical model. Results indicate that the concentration variation in the reservoirs is important to solute transport in the aquifer-aquitard system in the laboratory-controlled experiment, and the new analytical model outperforms the previous models in interpreting experimental data. The global sensitivity analysis demonstrates that the output concentration of solute transport in the aquifer-aquitard system is most sensitive to the volume of water in the pre-inlet reservoir. The contribution of the diffusion effect to the total mass flux of tracer crossing the aquifer-aquitard interface is much smaller than the contribution of the dispersive and advective effects.

Low-Cost Polyethylene Terephthalate Fluidic Sensor for Ultrahigh Accuracy Measurement of Liquid Concentration Variation

A low-cost polyethylene terephthalate fluidic sensor (PET-FS) is demonstrated for the concentration variation measurement on fluidic solutions. The PET-FS consisted of a triangular fluidic container attached with a birefringent PET thin layer. The PET-FS was injected with the test liquid solution that was placed in a common path polarization interferometer by utilizing a heterodyne scheme. The measured phase variation of probe light was used to obtain the information regarding the concentration change in the fluidic liquids. The sensor was experimentally tested using different concentrations of sodium chloride solution showing a sensitivity of 3.52 ×104 deg./refractive index unit (RIU) and a detection resolution of 6.25 × 10−6 RIU. The estimated sensitivity and detection resolutions were 5.62 × 104 (deg./RIU) and 6.94 × 10−6 RIU, respectively, for the hydrochloric acid. The relationship between the measured phase and the concentration is linear with an R-squared value reaching above 0.995.

The Effect Of Giving Banana Stem Compos With EM4 Concentration Variation And Urea Fertilizer On The Growth Of (Pepper nigrum L.) Cuttings Of Malonan 1 Variety

This research was conducted at the Experimental Garden of Widya Gama Mahakam University Samarinda, Faculty of Agriculture, Jalan KH. Wahid Hasyim. The study was conducted in January - April 2020. This study used a factorial randomized block design (RBD) with 2 treatment factors and 3 replications. The first factor was the application of banana stem compost with various concentrations of EM4 consisting of 4 levels, namely P0 = banana stem compost without EM4, P1 = banana stem compost with EM4 concentration of 50 ml L-1 water, P2 = banana stem compost with EM4 concentration of 75 ml. L-1 water, P3 = banana stem compost with a concentration of EM4 100 ml L-1 water and the second factor is the dose of urea fertilizer which consists of 4 levels, namely, D0 = control, D1 = 1 g urea / polybag, D2 = 2 g urea / polybag, D3 = 3 g urea / polybag. The results of the research giving banana stem compost with variations in the concentration of EM4 and the dose of urea fertilizer and the interaction of the two treatments had a very significant effect on plant height at the age of 20, 40, 60 and 80 DAS, with the best treatment P3 = 28.67 cm, D3 = 28, 21 cm and P3D3 = 32.33 cm, then had a very significant effect on the number of shoots at the age of 60 and 80 DAS with the best treatment P3 = 6.67 fruit, D3 = 6.17 fruit and P3D3 = 8.33 fruit, and very influential significant on the number of leaves at the age of 40, 60 and 80 DAS with the best treatment P3 = 8.58 strands, D3 = 8.83 strands and P3D2 = 10.67 strands.