Volume Of Water Content Research Articles

Effects of heavy rainfall on the slope stability – A case study on Imogiri Cemetery: The graveyard complex of Mataram Royal Kings

Rainfall is the most common cause of landslides in Indonesia. On March 17, 2019, a landslide occurred in the Imogiri Cemetery, Mataram Royal Kings Graveyard Complex. It was expected to have been triggered by heavy rainfall of 148 mm d–1 intensity. This research aims to determine the effect of rainfall on the slope stability on the landslide at the Imogiri Cemetery. The study was carried out by slope stability modelling using Geostudio software. Rainfall information and soil characteristics data obtained from testing soil samples in the Soil Mechanics Laboratory, Civil and Environmental Engineering, Universitas Gadjah Mada, were used as input on the software. The output of the analysis is the factor of safety (FS) value, defined as the ratio of the shear strength to the shear stress. Without the rains, the FS value is about 2.44, which means the slope stability is stable. After heavy rainfall, the FS value decreased to 1.209 at the end of the simulation, which indicates happen the slope instability. Based on the simulation, the FS value depends on the volume of water content and hydraulic conductivity of the soil. Result of this study shows that heavy rainfall can trigger slope instability in the Imogiri Cemetery.

Bacillus subtilis and surfactant amendments for the breakdown of soil water repellency in a sandy soil

Soil water repellency (SWR) is an agricultural concern as it limits plant available water, leading to decreased crop yields at times when a drying climate and expanding population place increasing pressure on food production. Here we assessed a microbial inoculation that secretes biosurfactants and lipolytic enzymes and a chemical surfactant's ability to mitigate SWR. We applied either Bacillus subtilis (Gm), surfactant (Gs), Bacillus subtilis with surfactant (Gms) or no treatment (G) to a gamma-irradiated, naturally water-repellent, agricultural soil, with the same soil as an un-sterilised, untreated control (C). Soil water content and the persistence of SWR in a water-repellent core (4 × 4 × 3 cm) were measured during 19 days of repeated soil wetting and drying. Meso-scale, 3D electrical resistivity tomography (ERT) was developed for the continuous, non-destructive measurement of the patterns and volume of water content in the soil, however, effectiveness was limited as the electrical current (5 mA) restricted microbial activity. Destructive measurements of soil water content and potential SWR were conducted in 1 cm soil layers throughout each core. The persistence of SWR decreased over time in all treatments apart from treatment G. SWR was removed by day 12 within the Gm treatment, and was not exhibited immediately after wetting in treatments Gs and Gms. The Gs treatment also increased water content immediately while treatment Gm increased water content after eight days of incubation, with soil saturated by day 19 of the incubation. Persistence of SWR significantly varied with depth, with the highest persistence in the 1–2 cm soil layer. Our findings illustrate that in order to remove SWR, without the effect of chemical surfactants, first microbial degradation of the molecules attributing to SWR has to occur. This indicates a biological mechanism as the driver for non-reversible SWR breakdown rather than a solely physical process.

Effects of various biodiesel blends on LHR engine

Purpose This paper aims to compare the performance, emission and combustion characteristics of E20 biodiesel with diesel-water emulsion and eucalyptus water emulsion. Design/methodology/approach This research expounds the trans-esterification process apparently. Various biodiesel blends were made to go through the trans-esterification process to make it suitable for feeding them into the low heat rejection (LHR) engine. E20 biodiesel – 20% of eucalyptus oil by volume with diesel was chosen to carry out the research as it was found to be the best blend with diesel. The volume of water content in diesel water emulsions was varied by 5, 10 and 15% in DWM1 (Diesel Water Mixture1), DWM2 (Diesel Water Mixture2) and DWM3 (Diesel Water Mixture3), respectively. Similarly, the volume of water content in eucalyptus water emulsions was varied with emulsification ratio of E20 biodiesel. Partially stabilized zirconia was coated over top surface of the piston and valve facing of the LHR engine. Findings From the researches carried out, DWM3 (Diesel Water Mixture3) was found to be superior when compared with other diesel-water emulsions in LHR engine. The overall efficiency was found to be higher for EWM3 than other biofuels tested the in LHR engine. Originality/value This investigational experiment can be further extended to multi-cylinder engine and to improve the cetane number, Di ethyl ester (DEE) fuel additives can be added.

Electrical Resistivity Imaging of Suspected Seepage Channels in an Earthen Dam in Zaria, North-Western Nigeria

To determine and map the subsurface conditions of a dam, a 2D electrical resistivity tomography study was carried out within the two flanks of Zaria dam at Shika. This was done to ascertain if the variations in the volume of water content in the dam is due to an anomalous seepage beneath the subsurface or seasonal effects. On the basis of the interpretation of the acquired data, various zones of relatively uniform resistivity values were mapped and identified. The first zone is characterized by moderate resistivity values of 150 - 600 ohm-m. It represents unsaturated topsoil with thicknesses varying from 1 - 4.5 m. The second (intermediate depth) resistivity zone, with values ranging from 5 - 100 ohm-m and thickness varying from 3.5 - 10 m, represents a silt clay layer with high moisture content. The third resistivity zone represents fairly weathered granite and is characterized by relatively high resistivity values ranging from 700 - 6000 ohm-m. The available borehole log data correlated well with the pseudo-sections in relation to the obtained resistivity values and depth. Zones of relatively low resistivity within the bedrock are interpreted to represent potential seepage pathways. Hence, this geophysical method can be successfully used to delineate and map these seepage pathways within the subsurface of the earth dam.

Evaluation of Method of Line (MOL) for Solution of Soil Water Flow Equations and Comparison with Finite Element Method (FEM)

The objective of this research is to evaluate Method of Line (MOL) used for solution of water flow equations through porous media using MATLAB package functions for solution of ordinary differential equations ODE,s , instead of writing long programs codes. sink & source term to MOL model were included. Then Comparing MOL model with another model that uses finite element method in solving water flow equations(FEM) in one dimensional flow using computer program code in FORTRAN. Two cases were examined for evaluation and comparison of these two models. Firstly, infiltration phenomena using sandy soil was studied with the same parameter for both models. Results show that there is a divergence between the two models along time of 60 minutes of infiltration. Changes of moisture content with soil depth were sharp with FEM model. Second case, data of the volume of water content for wheat field where used taking irrigation and evaporation into account, along the growth period of wheat crop and different depths up to 100 cm. Results show that output of FEM model has high degree of agreement with the measured data for all depths and along all period of growth. Data given by MOL model were less in values than measured data for all depths and along all period of wheat growth time.

Measuring Soil Water Content of Real Slopes by the Time Domain Reflectometry

Understanding the behavior and content of soil water is important for analysis of its infiltration. Tensiometers are conventionally used to measure the suction pressure. The suction pressure is then converted into the volume of water content by using conversion equation. The problem with this method is that the water content, computed by conversion equation, is remarkably different depending on the equation used. Our research intended to give the relationship between the volume of water content and the suction pressure. Both of them were measured at the same time on real slopes by time domain reflectometry (TDR), which is capable of directly measuring the volume of water content. The volume of water content computed by TDR was compared with the water content converted from the suction pressure by the traditional method to study the accuracy and characteristics of TDR. Here, we also discuss the results of the comparison.