Browsing by Author "North Dakota State University"

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    Color removal from textile wastewater by using treated flute reed in a fixed bed column
    (2010-04-01) Duangrat Inthorn; Kannika Tipprasertsin; Paitip Thiravetyan; Eakalak Khan; Mahidol University; King Mongkuts University of Technology Thonburi; North Dakota State University
    This study investigated the ability of acid treated flute reed to adsorb color (dye) from synthetic reactive dye solutions, and actual dyeing and printing textile wastewaters in a laboratory scale fixed bed column. The effects of particle size, initial reactive dye concentration, bed depth and flow rate on adsorption performances were examined. The results from experiments with synthetic reactive dye solutions showed that the volume treated (until the breakthrough occurred) increased with decreasing particle size, influent reactive dye concentration and flow rate, and increasing bed depth. The bed depth service time model was suitable for describing the experimental data. The treated flute reed was able to reduce color efficiently, 99% for dyeing textile wastewater with ten adsorption columns in series and 78% for printing textile wastewater with a single adsorption column. The difference in the numbers of columns used for the two types of actual textile wastewater led to a substantial discrepancy in suspended solids removal, 99% for dyeing wastewater and 12% for printing wastewater. Similar pH and chemical oxygen demand (COD) results were obtained for the two types of textile wastewater. The acid pretreatment of flute reed resulted in dramatic decreases in pH after the adsorption and very acidic effluents (pH 3). Increases of COD after the adsorption due to organic leaching from the treated flute reed were observed. A different pretreatment method to solve these pH and COD problems is needed before flute reed can be used in practice. Copyright Copy; Taylor & Francis Group, LLC.
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    Decolorization of basic, direct and reactive dyes by pre-treated narrow-leaved cattail (Typha angustifolia Linn.)
    (2004-09-01) Duangrat Inthorn; Siritham Singhtho; Paitip Thiravetyan; Eakalak Khan; Mahidol University; King Mongkuts University of Technology Thonburi; North Dakota State University
    The efficiency of basic, direct and reactive dye removal from water by narrow-leaved cattail (NLC) powder treated with distilled water (DW-NLC), 37% formaldehyde+0.2 N sulfuric acid (FH-NLC), or 0.1 N sodium hydroxide (NaOH-NLC) at various pH levels (3, 5, 7, and 9) was tested. Desorption of the adsorbed dyes was also investigated. The type of NLC treatment and pH of the dye solution had little effect on removal of basic dyes, and efficiencies ranged from 97% to 99% over the range of pH used. Over a wide range of pH levels, all types of treated cattail powder had negative charges and probably attracted the basic dyes possessing positive charges. Efficiency of removal by the three NLC treatments ranged from 37% to 42% for direct dyes and from 22% to 54% for direct dyes at pH 7. The pH of the dye solution had substantial effects on the efficiency of removal in direct and reactive dyes. Dye removal was highest at pH 3, with 99% for a direct dye (Sirius Red Violet RL) and 96% for a reactive dye (Basilen Red M-5B). There was mutual attraction between negatively charged direct dye molecules and positively charged molecules on the surface of the FH-treated cattail. In tests of desorption of dyes from cattail in distilled water, the desorption percentage for FH-NLC after adsorbing basic, direct and reactive dyes was 6%, 10% and 35%, respectively, which indicated a chemisorption mechanism for basic and direct dyes and some physiosorption for reactive dyes. © 2004 Elsevier Ltd. All rights reserved.
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    The emergence of business-to-consumer e-commerce: New niche formation, creative destruction, and contingency perspectives
    (2009-01-01) Chanchai Tangpong; Muhammad Islam; Nongkran Lertpittayapoom; North Dakota State University; Mahidol University
    This study examines the emergence of business-to-consumer (B2C) e-commerce from new niche formation, creative destruction, and contingency perspectives. Based on multiretail-sector data, this study supports the contingency perspective. The findings suggest that in digitally related sectors, B2C e-commerce has emerged through a creative destruction process whereby B2C e-commerce expands at the expense of traditional retailing; thus, addressing the e-commerce trend becomes traditional firms' strategic imperative. Conversely, in digitally unrelated sectors, B2C e-commerce has emerged through a new niche formation process whereby B2C e-commerce coexists with traditional retailing; thus, embracing the e-commerce trend becomes the traditional firms' strategic choice. © 2009 Baker College.
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    Photodegradation of (E)- and (Z)-Endoxifen in water by ultraviolet light: Efficiency, kinetics, by-products, and toxicity assessment
    (2020-03-15) Marina Ariño Martin; Jayaraman Sivaguru; John McEvoy; Prinpida Sonthiphand; Andre Delorme; Eakalak Khan; North Dakota State University; University of Nevada, Las Vegas; Chulalongkorn University; Valley City State University; Bowling Green State University; Mahidol University
    © 2019 Elsevier Ltd Endoxifen is an effective metabolite of a common chemotherapy agent, tamoxifen. Endoxifen, which is toxic to aquatic animals, has been detected in wastewater treatment plant (WWTP) effluent. This research investigates ultraviolet (UV) radiation (253.7 nm) application to degrade (E)- and (Z)-endoxifen in water and wastewater and phototransformation by-products (PBPs) and their toxicity. The effects of light intensity, pH and initial concentrations of (E)- and (Z)-endoxifen on the photodegradation rate were examined. Endoxifen in water was eliminated ≥99.1% after 35 s of irradiation (light dose of 598.5 mJ cm−2). Light intensity and initial concentrations of (E)- and (Z)-endoxifen exhibited positive trends with the photodegradation rates while pH had no effect. Photodegradation of (E)- and (Z)-endoxifen in water resulted in three PBPs. Toxicity assessments through modeling of the identified PBPs suggest higher toxicity than the parent compounds. Photodegradation of (E)- and (Z)-endoxifen in wastewater at light doses used for disinfection in WWTPs (16, 30 and 97 mJ cm−2) resulted in reductions of (E)- and (Z)-endoxifen from 30 to 71%. Two of the three PBPs observed in the experiments with water were detected in the wastewater experiments. Therefore, toxic compounds are potentially generated at WWTPs by UV disinfection if (E)- and (Z)-endoxifen are present in treated wastewater.
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    Photolytic fate of (E)- and (Z)-endoxifen in water and treated wastewater exposed to sunlight
    (2021-06-01) Marina Ariño Martin; Jayaraman Sivaguru; John McEvoy; Prinpida Sonthiphand; Eakalak Khan; North Dakota State University; University of Nevada, Las Vegas; Chulalongkorn University; Bowling Green State University; Mahidol University
    Endoxifen is the main active metabolite of a common cytostatic drug, tamoxifen. Endoxifen has been recently detected in the final effluent of municipal wastewater treatment plants. The antiestrogenic activity of endoxifen could bring negative effects to aquatic life if released to the water environment. This study elucidated the fate and susceptibility of (E)- and (Z)-endoxifen (2 μg mL−1, 1:1 wt ratio between the two easily interchangeable isomers) in wastewater and receiving surface water to sunlight. Phototransformation by-products (PBPs) and their toxicity were determined. Sunlight reduced at least 83% of endoxifen concentration in wastewater samples, whereas in surface water samples, 60% of endoxifen was photodegraded after 180 min of the irradiation. In ultrapure water samples spiked with endoxifen, PBPs were mainly generated via con-rotatory 6π-photocyclization, followed by oxidative aromatization. These PBPs underwent secondary reactions leading to a series of PBPs with different molecular weights. Eight PBPs were identified and the toxicity analysis via the Toxicity Estimation Software Tool revealed that seven of these PBPs are more toxic than endoxifen itself. This is likely due to the formation of poly-aromatic core in the PBPs due to exposure to sunlight. Therefore, highly toxic PBPs may be generated if endoxifen is present in water and wastewater exposed to sunlight. The presence, fates and activities of these PBPs in surface water especially at locations close to treated wastewater discharge points should be investigated.
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    Pinning of domains for fluid-fluid phase separation in lipid bilayers with asymmetric dynamics
    (2011-03-21) Waipot Ngamsaad; Sylvio May; Alexander J. Wagner; Wannapong Triampo; North Dakota State University; University of Phayao; Mahidol University
    We propose a physical mechanism for the arrest of domain coarsening in a system of two apposed two-dimensional binary fluids. The two fluids are subject to a dynamic asymmetry: strong friction with the environment allows domains in one fluid layer (the "bottom" fluid) to grow only diffusively, whereas hydrodynamic flow leads to initially faster growth in the apposed fluid (the "top" layer). The two fluids are energetically coupled so that domains of similar type interact favorably across the two fluids. Using lattice Boltzmann simulations we observe that at a certain length scale, which is independent of the coarsening state in the bottom layer, domain growth in the top layer comes to an arrest. A phenomenological model suggests the pinning of domains across the two fluids to cause the arrest in domain growth. The pinning results from the interplay between line tension and domain coupling strength across the two fluids. We apply our model to a lipid bilayer for which we calculate the length scale of the dynamically arrested domains in the top layer. We find domain extensions of about or somewhat larger than 20 nm. Potential applications of our pinning model are to mixed lipid bilayers that tend to phase separate and are subject to a dynamic asymmetry; these include model membranes on a solid support and lipid rafts in the plasma membrane. © 2011 The Royal Society of Chemistry.
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    Salmonella phages isolated from dairy farms in Thailand show wider host range than a comparable set of phages isolated from U.S. dairy farms
    (2014-08-06) Sarach Wongsuntornpoj; Andrea I. Moreno Switt; Peter Bergholz; Martin Wiedmann; Soraya Chaturongakul; Mahidol University; Cornell University; North Dakota State University; Andres Bello National University
    Salmonella is a zoonotic pathogen with globally distributed serovars as well as serovars predominantly found in certain regions; for example, serovar Weltevreden is rarely isolated in the U.S., but is common in Thailand. Relative to our understanding of Salmonella diversity, our understanding of the global diversity of Salmonella phages is limited. We hypothesized that the serovar diversity in a given environment and farming system will affect the Salmonella phage diversity associated with animal hosts. We thus isolated and characterized Salmonella phages from 15 small-scale dairy farms in Thailand and compared the host ranges of the 62 Salmonella phage isolates obtained with host range diversity for 129 phage isolates obtained from dairy farms in the U.S. The 62 phage isolates from Thailand represented genome sizes ranging from 40 to 200. kb and showed lysis of 6-25 of the 26 host strains tested (mean number of strain lysed = 19). By comparison, phage isolates previously obtained in a survey of 15 U.S. dairy farms showed a narrow host range (lysis of 1-17; mean number of strains lysed = 4); principal coordinate analysis also confirmed U.S. and Thai phages had distinct host lysis profiles. Our data indicate that dairy farms that differ in management practices and are located on different continents can yield phage isolates that differ in their host ranges, providing an avenue for isolation of phages with desirable host range characteristics for commercial applications. Farming systems characterized by coexistence of different animals may facilitate presence of Salmonella phages with wide host ranges. © 2014 Elsevier B.V.