Sudhakar Madhav Rao

Introduction: Cement stabilization rapidly increases strength, lowers permeability, and enhances durability for ground improvement and earth block stabilization. The significance of dry density (DD) and OPC content in predicting the compressive strengths of cemented cylindrical and block specimens was recognized by earlier researchers who developed predictive equations for cylindrical and block specimens. The existing approaches are limited because the exponents of the material properties vary with soil type and the type of specimen (cylindrical or block) used. Equations to predict the compressive strengths of cemented block specimens in the soaked state are unavailable. Methods: Equations are proposed in this study use the simple DD×OPC product for both cylinders and block specimens. The sand, clay and plasticity index of the block soils varied from 7-78%, 4.5-25%, and non-plastic to 20% respectively. Furthermore, the equations (based using published data sets) enable reliable compressive strength predictions of cemented cylindrical and block specimens in soaked and unsoaked conditions. Results and Discussion: A single equation predicts the compressive strengths of cylinders made from four soil types: SC (Sandy Clay), CL (Clay), ML (Silt), and SM (Sandy Silt). A single equation predicts the compressive strengths of block specimens made from two soil types: SC and CL. The x and y exponents for OPC and DD terms are obtained from R2 (coefficient of determination) optimization of strength versus DDy × OPCx relations. Data analysis showed that cemented blocks with 5% OPC will meet load-bearing walls criteria (unsoaked strength > 4 MPa, soaked strength = 2 MPa) at densities of 1.65 to 1.85 g/cc; 7% OPC blocks will meet criteria at dry densities of 1.65 to 1.8 g/cc. Most blocks with 4% OPC were only suitable for non-load-bearing walls except at the density of 1.85 g/cc.

Cureus Journals Gasoline stations in Bangalore, Karnataka, India, were found to pollute groundwater with BTEX (benzene, toluene, ethylbenzene, and xylenes) compounds due to leakage from subterranean storage tanks. Prior global research has isolated several BTEX degraders from petroleum-contaminated soils. The success of earlier studies prompted the isolation of bacterial species from Bangalore’s gasoline-contaminated groundwater and soil samples for BTEX removal. Pseudomonas sp. and Bacillus haynesii were isolated from gasoline-contaminated soil and groundwater samples by enriching the cultures with toluene. Identification of aerobic bacteria isolates from soil and groundwater samples was performed by the 16S rRNA method. The B. haynessii, isolated from the hydrocarbon-contaminated groundwater, is a novel culture that has not been used as a BTEX degrader. Toluene was selected owing to its occurrence in Bangalore’s groundwater and the hydrocarbon’s potential to create major health issues. Greater cell reduction was observed with B. haynesii implying them to be less tolerant to toluene contamination. The Pseudomonas sp. bacteria degraded toluene at a steady rate of 0.127 h⁻¹, leading to 38%, 50%, 84%, and 100% mineralization after 2 h, 6 h, 12 h, and 24 h, respectively. Combining the findings of this study and of other research indicated that the rate of toluene decomposition is retarded by the presence of co-compounds, increased toluene concentrations, and depleted dissolved oxygen levels. Compared to B. haynesii, Pseudomonas sp. aerobically digested greater amounts of toluene (concentration range = 5 to 300 mg/L), suggesting that it is a superior choice for biodegradation of Bengaluru’s toluene-contaminated groundwater (concentration range = 0.062 to 0.153 mg/L) by using appropriate field technologies. The study also showed that Bangalore’s BTEX degraders can mineralize toluene concentrations encountered in contaminated environments or those used in previous laboratory investigations.

The manuscript by Joshi examines the pedogenic characterization of alluvial soils from Rajasthan, India. The author has performed extensive physical and chemical tests as part of the study to understand the soil illuviation process. The manuscript wi...