Environmental Health Commons^™

Cytotoxicity And Mutagenicity Of Disinfection Byproduct Mixtures Formulated Using Free Chlorine And Monochloramine, Yonas Ghebremedhin

Graduate Theses and Dissertations

Bioassays have been used extensively to assess various toxicity endpoints of drinking water disinfection byproducts (DBPs), but an emphasis on single compounds prevails. In this research, DBP mixtures were assessed using a cytotoxicity test with Chinese Hamster Ovary (CHO) cells and an Ames fluctuation test with Salmonella typhimurium TA-98 and TA-100 with and without S9 rat liver homogenate. Seven whole mixture DBP concentrates were formulated using reconstituted natural organic matter (NOM) extracts from the Upper Mississippi River using scaled disinfectant dosing protocols with free chlorine and monochloramine in the presence and absence of added bromide. DBPs were identified by gas …

Fouling And Aging In Membrane Filtration : Hybrid Afm-Based Characterization, Modelling And Reactive Membrane Design, Wanyi Fu

Dissertations

Membrane filtration has been extensively used in water and wastewater treatment, desalination, dairy making, and biomass/water separation. However, membrane fouling, aging and insufficient removal efficiency for dissolved organic matters remain major challenges for wider industrial applications. In order to tackle these challenges, this doctoral dissertation investigates mechanisms of membrane fouling and development of antifouling membrane filtration technologies. Specifically, four major research areas are explored: (i) nanoscale physicochemical characterization of the chemically modified polymeric membranes; (ii) quantitative modelling between membrane properties and membrane fouling and defouling kinetics; (iii) development of quantitative structure-activity relationships for membranes that undergo thermal and chemical aging …

Internal Design Of A Hydroponics Greenhouse For Tri Cycle Farms, Sarah Gould

Biological and Agricultural Engineering Undergraduate Honors Theses

Hydroponics is the agricultural technique of growing plants without soil, using other growing media and added nutrients in a solvent. It is an attractive agricultural method over conventional agriculture because it is more water efficient, is less labor intensive, yields higher quality crops in less time, and is easier to control. According to the Digital Journal, “hydroponics crop value is anticipated to grow to USD 27.29 Billion by 2022 at an estimated CAGR of 6.39% from 2015 to 2020” (Sawant, 2016). Alongside this growing market acceptance for hydroponics, there is also a local demand that requires only a small transportation …

Validation Of A Low-Cost Sensor For Development Of Wearable And Handheld Spectrometers, Justin Leslie Cathey

Graduate Research Theses & Dissertations

This study examined the possibility of creating a quantitative radiometric spectrometer from a low-cost relative radiometric spectrometer sensor through the use of statistical analysis and development of a correction factor (p > 0.05). Radiometric spectrometers are able to measure and fully characterize the radiometric and photometric characteristics of light, while relative spectrometers are not able to fully, quantitatively characterize the radiometric response from a light source, thus they are less expensive. The spectrometer created in this research is able to measure and produce comparative lighting parameters as well as an actual radiometer spectrometer.

The photoreceptors cells within the human eye allow …