Drew Johnson

Drew Johnson
University of Texas at San Antonio | UTSA · Department of Civil and Environmental Engineering

About

23
Publications
1,270
Reads
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288
Citations
Citations since 2017
4 Research Items
112 Citations
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20172018201920202021202220230510152025
20172018201920202021202220230510152025
20172018201920202021202220230510152025

Publications

Publications (23)
Article
This study focuses on assessing the heat transfer rate and structural stability of a novel self-operating energy pile based on the principle of a thermo-syphon. Specifically, this new energy pile, referred to as a“thermo-syphon helical pile”(THP), is formed by pressurizing a hollow helical pile with carbon dioxide (CO2) to form a heat pipe,where sp...
Article
This study focuses on assessing the heat transfer rate and structural stability of a novel self-operating energy pile based on the principle of a thermo-syphon. Specifically, this new energy pile, referred to as a “thermo-syphon helical pile” (THP), is formed by pressurizing a hollow helical pile with carbon dioxide (CO2) to form a heat pipe, where...
Article
The desalination processes produces highly concentrated brine effluent which is costly to dispose of for inland desalination facilities. The current study uses a membrane evaporation process to reduce brine volumes. Membrane evaporation was evaluated at the bench scale for different brine flow rates, airflow rates and air temperatures, extent of fo...
Article
Full-text available
PCBs have been banned since the late 1970s, but concentrations still exist in sediments and riverine fish and continue to exceed regulatory limits which can result in negative health effects. This study looks at historical records of PCB and Arochlor concentrations in surface water, sediments, and fish tissue for the Lower Leon Creek, Bexar County...
Article
A new method is explored for subsurface irrigation where the plant root structure is used as the subsurface water distribution system. Plants are severed at the stem and the stem stump is attached to a pressurized water source such that water may permeate into surrounding soil through the existing buried root system. This pressurized root system se...
Article
Nanoparticles are considered potential environmental contaminants because of reported toxicity to biota in the environment. As such, there is interest in understanding how to remove nanoparticles from waters. This study investigated membrane filtration behaviors of 70-nm alumina oxide nanoparticle when aggregated under diffusion limited aggregation...
Article
Polymer-infused plant roots can be created without soil excavation by infusing polymer into the roots of plants through the easily accessible above-surface plant stems. Efficacy of this technique for use in soil stabilization applications involves assessing the durability of polymer-infused plant roots. Polymer content was determined for infused Ar...
Article
This research investigates the use of polymer-infused roots for soil-improvement applications. By infusing polymer through the easily accessible above-surface plant stems, polymer-infused roots can be created without subsurface excavations. Evaluation of this technique involves identifying the improvements from polymer-infused roots by measuring in...
Article
Nanofluids are reported to have enhanced thermal conductivities resulting from nanoparticle aggregation. The goal of this study was to explore through experimental measurements, dispersed and aggregated morphology effects on enhanced thermal conductivities for Al2O3 nanoparticles with a primary size of 54.2 ± 2.0 nm. Aggregation effects were invest...
Article
By infusing a thermoset epoxy polymer into the root system of a plant, we aim to create an in situ plant-polymer composite material of high tensile strength resistant to biodegradation and suitable for soil stabilization applications. Microscopy imaging, volume and mass measurements, thermogravimetric analysis, and tensile testing were conducted to...
Article
Controversy and the ambiguity exist in the scientific literature for the question of if nanoparticles truly enhance heat and mass transfer. This study experimentally explored effects of non-aggregating spherical SiO2 nanoparticles on oxygen and NaCl mass transfer. No mass transfer enhancements were found in the presence of nanoparticles. Oxygen tra...
Conference Paper
In this study, plant root templated georeinforcements are created by infusing polymer under pressure into the roots of Ruellia Squarrosa grown in soil. The effect of infusing polymer into the plant roots is evident and results in 22 kPa of soil shear strength enhancement. To ascertain the permanency of these georeinforcements, acid hydrolysis was p...
Article
Counter-current parallel flow membrane contactors were studied to estimate likely formaldehyde removal rates from air occurring during membrane air humidification and evaporative cooling applications. A mathematical model and experimental measurements of formaldehyde removal are presented to assess the impact of possible operating conditions and co...
Conference Paper
Synthetic organic polymers are typically used in water treatment to coagulate colloids and enhance the performance of sedimentation and filtration processes. This research investigates polyacrylamide (PAM) application for use in unlined conveyance channels to decrease water infiltration rates. Column studies were conducted with well-sorted sand to...
Article
Improvements in irrigation efficiency are well documented when changing from flood to sprinkler irrigation methods; however, other impacts to the watershed associated with this change are not well known. The resulting impacts to a river basin hydrology when irrigation and conveyance methods are changed are the focus of this study. In an attempt to...
Article
This paper describes the potential use of hollow fiber membranes in evaporative cooling applications for space air-conditioning. Duct-mountable hollow fiber membrane bundles and arrays are utilized as contactors for the delivery of liquid water to an air stream in a heating, ventilating air-conditioning duct. A series of experimental and analytical...
Article
Membrane recovery of light non-aqueous phase liquids (LNAPLs) was studied. Small membrane modules, operated in a sealed end configuration, were pressurized with several LNAPLs in order that membrane permeability and fouling processes might be characterized. The mitigation of membrane fouling via backpulsing was optimized for backpulse amplitude, fr...
Article
Iron fouling characteristics of gas permeable composite and wetted microporous hollow fiber membranes were studied. Membrane modules, operated in the sealed end configuration, were pressurized with oxygen and enclosed within a tubular shell. A solution consisting of tap water and ferrous sulfate was metered though the shell side of the module. The...
Article
Gas transfer through hollow fiber membranes allows for rapid transfer kinetics, high transfer efficiencies, and the ability to precisely control transfer rates. Despite these advantages, membrane gas transfer has not been used extensively in industrial fermentation or wastewater treatment. Module plugging and biofouling are problematic with current...
Article
Full-text available
In this study, unconfined hollow-fiber membrane modules are designed to be attached to a rotating arm that pulls the fibers through water. This use of unconfined membranes is well suited to environmental applications where waters often contain high solids concentrations that can rapidly clog or foul tightly packed conventional tubular membrane modu...
Article
Full-text available
The transfer performance and power requirements of unconfined sealed end hollow fiber membranes were studied. Membrane modules, operated in the sealed end mode, were pressurized with oxygen and placed within a submerged rectangular jet discharge. This design is especially well suited for use in waters containing high solids concentrations. The memb...
Article
Full-text available
The mass transfer characteristics of gas permeable, hollow fiber membranes in a liquid jet mixed reactor are studied. A membrane module, operated in the sealed-end mode, was pressurized with oxygen at the base of the fibers and centered within a submerged jet discharge. Unlike conventional membrane module designs, this configuration did not have th...
Article
Large quantities of water are associated with the production of coalbed methane (CBM) in the Powder River Basin (PRB) of Wyoming. The chemistry of co-produced water often makes it unsuitable for subsequent uses such as irrigated agriculture. However, co-produced waters have substantial potential for a variety of beneficial uses. Achieving this pote...

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