Matching Items (5)
151466-Thumbnail Image.png
Description
In today's world where sustainability is of prime importance, energy efficient method for sea water desalination and waste water treatment is gaining attention. State of art Reverse Osmosis (RO) method has high power consumption; hence people are diverting their attention towards Forward Osmosis (FO). It has been determined that the

In today's world where sustainability is of prime importance, energy efficient method for sea water desalination and waste water treatment is gaining attention. State of art Reverse Osmosis (RO) method has high power consumption; hence people are diverting their attention towards Forward Osmosis (FO). It has been determined that the support membrane hydrophilicity plays an important role impacting the water flux through membranes in forward osmosis processes. The support layer of commercially available thin film composite RO membranes has been modified with a hydrophilic polymer Polyvinyl Alcohol (PVA). Previous research has demonstrated that PVA coating of the top selective layer of RO membranes has decreased selective layer roughness and increased selective layer hydrophilicity. The role of PVA with 2 different PVA cross-linkers: Maleic Acid (MA) and Glutaraldehyde (GA) at 2 different concentrations of 10% and 50% have been investigated. The hydrophilicity, water flux, salt flux and rejection of the neat and modified membranes in Reverse Osmosis and Forward Osmosis are measured. Maleic Acid when used with PVA at a lower degree of cross linking (10%) shows significant improvement in water flux in SW membranes in comparison to Glutaraldehyde cross-linked PVA coated membranes. This improvement is not so significantly observed in BW membranes due to its lower porosity. PVA when used with a small amount of cross-linker shows promising results in increasing the hydrophilicity of TFC membranes enabling RO membranes to be used efficiently in FO processes.
ContributorsSaraf, Aditi (Author) / Lind, Dr. Mary (Thesis advisor) / Dai, Dr. Lenore (Committee member) / Nielsen, Dr. David (Committee member) / Arizona State University (Publisher)
Created2012
173391-Thumbnail Image.png
Description

Wilhelm Pfeffer published his book Osmotische Untersuchungen: Studien Zur Zellmechanik (Osmotic Investigations: Studies on Cell Mechanics) in 1877 during his time as a professor of botany at the University of Basel in Basel, Switzerland. Gordon R. Kepner and Eduard J. Stadelmann translated the book into English in 1985. Verlag von

Wilhelm Pfeffer published his book Osmotische Untersuchungen: Studien Zur Zellmechanik (Osmotic Investigations: Studies on Cell Mechanics) in 1877 during his time as a professor of botany at the University of Basel in Basel, Switzerland. Gordon R. Kepner and Eduard J. Stadelmann translated the book into English in 1985. Verlag von Wilhelm Engelmann in Leipzig, Germany, published the original book in German in 1877 and Van Nostrand Reinhold Company in New York, New York, published the English version in 1985. The book focuses on the cell mechanics of osmotic processes to explain why high pressure exists in plant cells. The book also provides one of the earliest detailed descriptions of the Pfeffer Cell, a devise Pfeffer had created to model and study osmosis in plant cells. The model helped Pfeffer propose theories for how osmosis affected metabolism, growth, and development of plant cells.

Created2017-05-09
173434-Thumbnail Image.png
Description

The Pfeffer Zelle (Pfeffer Cell Apparatus), invented by Wilhelm Pfeffer in 1877, measured the minimum pressure needed to prevent a pure solvent from passing into a solution across a semi-permeable membrane, called osmotic pressure. The apparatus provided Pfeffer with a way to quantitatively measure osmotic pressure. Pfeffer devised the apparatus

The Pfeffer Zelle (Pfeffer Cell Apparatus), invented by Wilhelm Pfeffer in 1877, measured the minimum pressure needed to prevent a pure solvent from passing into a solution across a semi-permeable membrane, called osmotic pressure. The apparatus provided Pfeffer with a way to quantitatively measure osmotic pressure. Pfeffer devised the apparatus in the 1870s at the University of Basel in Basel, Switzerland, and he described the Pfeffer Cell Apparatus in his 1877 book Osmotische Untersuchungen: Studien Zur Zellmechanik (Osmotic Investigations: Studies on Cell Mechanics). Pfeffer relied on nineteenth century experiments of Moritz Traube in Germany, who constructed artificial copper ferrocyanide membranes to study osmosis. The apparatus enabled Pfeffer to study osmosis and osmotic pressure as plants grow, and later researchers used it to explain how plants develop.

Created2017-10-24
173018-Thumbnail Image.png
Description

In 1972, Peter Mazur, Stanley Leibo, and Ernest Chu published, “A Two-Factor Hypothesis of Freezing Injury: Evidence from Chinese Hamster Tissue-culture Cells,” hereafter, “A Two-Factor Hypothesis of Freezing Injury,” in the journal, Experimental Cell Research. In the article, the authors uncover that exposure to high salt concentrations and the formation

In 1972, Peter Mazur, Stanley Leibo, and Ernest Chu published, “A Two-Factor Hypothesis of Freezing Injury: Evidence from Chinese Hamster Tissue-culture Cells,” hereafter, “A Two-Factor Hypothesis of Freezing Injury,” in the journal, Experimental Cell Research. In the article, the authors uncover that exposure to high salt concentrations and the formation of ice crystals within cells are two factors that can harm cells during cryopreservation. Cryopreservation is the freezing of cells to preserve them for storage, study, or later use. Mazur originally suggested the two factors in a 1970 paper, but that article was based on evidence from simple yeast cells. By using hamster cells in 1972, Mazur, Leibo, and Chu confirmed that Mazur’s two-factor hypothesis applied to more complex mammalian cells. The article dispelled the widely accepted notion that rapid cooling rates were safest for all cells, and instead showed that each kind of cell had a different optimal cooling rate depending on the solution in which it froze.

Created2021-03-02
172881-Thumbnail Image.png
Description

In 1972, David Whittingham, Stanley Leibo, and Peter Mazur published the paper, “Survival of Mouse Embryos Frozen to -196 ° and -269 °C,” hereafter, “Survival of Mouse Embryos,” in the journal Science. The study marked one of the first times that researchers had successfully cryopreserved, or preserved and stored by

In 1972, David Whittingham, Stanley Leibo, and Peter Mazur published the paper, “Survival of Mouse Embryos Frozen to -196 ° and -269 °C,” hereafter, “Survival of Mouse Embryos,” in the journal Science. The study marked one of the first times that researchers had successfully cryopreserved, or preserved and stored by freezing, a mammalian embryo and later transferred that embryo to a live mouse who gave birth to viable offspring. Previously, scientists had only been successful cryopreserving single cells, like red blood cells. Mammalian embryos, on the other hand, were more difficult to cryopreserve because they are more complex and therefore more easily weakened or destroyed by the formation of ice within its cells. Whittingham, Leibo, and Mazur’s work provided a successful model for mammalian embryo cryopreservation, a technology that later expanded to cryopreserve more complex embryos, such as human embryos.

Created2020-10-01