Effect of Fluid Chemistry on the Consolidation and Hydraulic Conductivity of Sand-Clay Liners

The clay swelling potential of sand-clay liners exposed to saline water or specific chemicals can influence their hydraulic conductivity and other consolidation properties. The effect of saline water or chemicals on the sand-clay liners was thus studied and evaluated. The consolidation characteristics of the sand-clay liner can be different when tested under different fluid media. Bentonite and cement grouts are chemicals that have a significant effect on the sand-clay liners. Cement and bentonite can be used to seal off the openings within the liner to repair a defect or a malfunction. In this study, Al-Qatif clay was used to form a sand-clay liner when mixed with fine-grained sand (clay is 20% by dry weight). Soil samples extracted from this liner were exposed to inorganic chemical solutions. NaCl and CaCl2 solutions with concentration ranges of 0.1%, 0.5%, and 1.5% were used. Acidic water with pH values of 4, 5, and 6 was similarly used as fluid media. The effects of NaCl, CaCl2, and water with different acidity on the consolidation characteristics and hydraulic conductivity were obtained and compared to those of the distilled water. The effects of grout materials containing bentonite (1%, 2%, and 3% by weight) and cement (2.5%, 5%, and 7.5% by weight) were also investigated. The addition of bentonite grout to the liner surface was found to improve its hydraulic conductivity. The cement effect on the compressibility was found to be very significant. The findings of this study can serve as a guide for selecting parameters in the design and assessment of sand-clay liners in semi-arid regions and coastal zones.

Hospitals and Laboratories on Paper-Based Sensors: A Mini Review

With characters of low cost, portability, easy disposal, and high accuracy, as well as bulky reduced laboratory equipment, paper-based sensors are getting increasing attention for reliable indoor/outdoor onsite detection with nonexpert operation. They have become powerful analysis tools in trace detection with ultra-low detection limits and extremely high accuracy, resulting in their great popularity in medical detection, environmental inspection, and other applications. Herein, we summarize and generalize the recently reported paper-based sensors based on their application for mechanics, biomolecules, food safety, and environmental inspection. Based on the biological, physical, and chemical analytes-sensitive electrical or optical signals, extensive detections of a large number of factors such as humidity, pressure, nucleic acid, protein, sugar, biomarkers, metal ions, and organic/inorganic chemical substances have been reported via paper-based sensors. Challenges faced by the current paper-based sensors from the fundamental problems and practical applications are subsequently analyzed; thus, the future directions of paper-based sensors are specified for their rapid handheld testing.

Identification of the Possible Negative Effect of the Brucite Drilling Reagent on the Employees Involved in the Wells Construction

In the technological processes of oil and gas wells construction, a variety of general-purpose inorganic chemical reagents are used. The ingress of these reagents into the body of drilling enterprises employees together with the inhaled air, ingested food (through the pores and mucous membrane) is currently not sufficiently studied. The work investigated the effect of the Brucite drilling reagent on the lung tissue of rats of the non-linear albino line. With the inhalation of the Brucite drilling reagent to rats, the dystrophic processes were observed in their lungs, which were accompanied by the development of chronic inflammation and an acute macrophage reaction. There was a significant increase in the size of perivascular infiltrates compared to the control (13370 ± 248.6) μm2) with 14-day administration of particles of the Brucite drilling reagent — (14867.21 ± 369.29) μm2, with 30-day administration — 15853, 87 ± 126.57. Also, morphometric analysis showed a significant decrease in the area of alveolar space, and the area of medium-caliber bronchus. In the lungs, the formation of many airless areas was noted, alternating with emphysematous — altered, the severity of which increased with the duration of exposure to the drilling reagent. The consequence of work with Brucite drilling reagent of the drilling enterprises employees can be professional, acute, and chronic diseases of the lungs, as well as specific sensitization of the body caused by the exposure to dust particles. In the future, it is planned to conduct a statistical analysis of the incidence rates with temporary disability, occupational diseases, and occupational poisoning among the employees in contact with the Brucite drilling reagent, and the development of efficient measures to reduce the harmful effects of the Brucite drilling reagent on the certain categories of specialists at the drilling enterprises.