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1
Botfield, Andrew Civil & Environmental Engineering Faculty of Engineering UNSW. "Kinetic modelling studies of As(III) oxidation in dark pH 3 and 8 Fenton - mediated and pH 8 Cu(II) - H2O2 systems." Awarded by:University of New South Wales. School of Civil and Environmental Engineering, 2006. http://handle.unsw.edu.au/1959.4/31969.
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In this thesis, a combination of laboratory experimentation under well defined conditions coupled with a kinetic modelling approach is used to verify the existence and respective kinetic rates of previously unconfirmed or postulated mechanisms that drive and limit dark Fenton (Fe(II)/H2O2) - mediated As(III) oxidation at pH 3 and 8 and dark Cu(II) - H2O2 - mediated As(III) oxidation at pH 8. Dark Fenton - mediated oxidation of As(III) at pH 3 is first examined and the effects of the variation in the concentration of reactants (As(III), Fe(II) and H2O2), oxygen, phosphate and organics (2 - propanol, formate, and citrate) are reported and analysed. The kinetic models developed for these systems show high applicability to full scale water treatment application and key mechanistic findings include the significance of the cycling of Fe(II) / Fe(III) via HO2 ???/O2 ??????, the effects of As(IV) termination reactions in the absence of oxygen and the retarding effects of phosphate due to the postulated formation of a Fe(III) - phosphate complex (at a derived rate constant of 2.2 x 106 M-1s-1, that also appears to have negligible kinetic activity in terms of reduction to Fe(II) by HO2 ???/O2 ??????). The work also demonstrates the significance of the free radical by products of formate and citrate oxidation by ???OH (HCOO???/CO2 ?????? and 3HGA???2???). The examination of the dark Cu(II) - H2O2 - mediated oxidation of As(III) at pH 8 with variation in the concentration of reactants (As(III), Fe(II) and H2O2), carbonate and organics (2 - propanol, formate and citrate) demonstrated for the first time the high applicability of this system to the pre - oxidation of As(III) in water treatment and mechanistically that ???OH and CO3 ?????? are the dominant As(III) oxidants in this system. The As(III) oxidant CO3 ??????, is suggested to be generated by the interaction of ???OH and O2 ?????? with the carbonate matrix, at the respective rate constants of 4.9 x 107 M-1s-1 and 5.5 x 106 M-1s-1. Examination of the dark Fenton - mediated oxidation of As(III) at pH 8 and the effects of variation in the concentration of reactants (As(III), Fe(II) and H2O2), carbonate, organics (2 - propanol, formate and citrate) and Cu(II) demonstrates the varied potential mechanistic pathways in relation to the generation of As(III) oxidants from the Fenton reaction, Fe(II) + H2O2 such as Fe(IV) and CO3 ?????? and the previously dismissed ???OH, due to the presence of Fe(II) - citrate complexes. This work also demonstrates and models the enhancement of As(III) oxidation in the presence of an additional transitional metal ion, Cu(II).
2
Bohn, Hinrich L., Henry Schreiber, and Loel R. Cooper. "Rainfall pH in Tombstone, Arizona, 1968-81." Arizona-Nevada Academy of Science, 1986. http://hdl.handle.net/10150/296369.
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From the Proceedings of the 1986 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 19, 1986, Glendale Community College, Glendale, ArizonaRainfall pH was measured at the Tombstone, Arizona, USDA-ARS station from 1968 to 1981. The summer rains were more acidic than the winter rains. The pH of the summer rains was about pH 5, the winter rains about pH 6, with considerable variation. The summer rain pH increased gradually over this period, coinciding with a general decrease of sulfur emissions from the nearest copper smelter at Douglas, Arizona, and from' all smelters in Arizona. The ionic composition of the rainwater was quantitively uncertain due to numerous changes in analytical procedures. The acidity was very roughly related to sulfur content. The inverse relation between acidity and Ca and Na content was somewhat clearer.
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Baker, Paul B. "Influence of pH 11 Water on Termiticide Degradation in Arizona." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001. http://hdl.handle.net/10150/216349.
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Termites continue to be Arizona’s number one urban pest. Factors that influence the persistence of termiticides are constantly under investigation. High pH has been identified as a potential concern for persistence in termiticides. I studied the influence of pH 11 water on five termiticides applied to commercial ABC fill 10 months post-treatment. In general, the addition of pH 11 water had little influence on termiticide persistence under Arizona conditions. Initially plots treated with Ph 11 water had higher residues than those that did not receive the treated water; over time these differences diminished.
4
de, la Haye Kate. "The behavioural consequences of reduced sea water pH in decapod crustaceans." Thesis, University of Plymouth, 2012. http://hdl.handle.net/10026.1/1028.
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The studies presented in this thesis were designed to investigate the effects of reduced sea water pH on the behaviour of intertidal decapod crustaceans, both within the context of the variations occurring naturally in the pH of rock pool habitats, and in relation to predicted changes to ocean pH resulting from ocean acidification and potential carbon dioxide (CO2) leaks from carbon capture storage (CCS) sites. Recent studies on marine fish have shown behavioural disruptions as a result of increased CO2 concentrations in sea water and reduced pH, but the effects on crustaceans are as yet unknown. The first two studies investigated the effects of reduced pH upon the olfactory behaviour of the prawn Palaemon elegans and the hermit crab Pagurus bernhardus, focussing on their responses to food odours. Short-term (five day) exposures to highly reduced pH (pHNBS = 6.60, 6.80) revealed disruptions to the chemo-sensory behaviour of both species with a reduction in their ‘sniffing’ response, and the inability of P. bernhardus to locate the chemical cue. This was also accompanied by elevated haemolymph chloride ions. in In a further study P. bernhardus was subjected to a longer exposure (60 days) and to a range of pH levels (pHNBS = 8.00, 7.90, 7.70, 7.35 and 6.80) in order to detect a threshold for the behavioural disruptions observed, and to determine if there would be any sign of acclimation over a longer period. A clear gradient in the disruptions to the chemo-sensory responses and survival rates of the hermit crabs, and disruption to a physiological marker (elevated haemolymph calcium ions), was found. Possible thresholds for disruption were also identified at levels that match predictions for ocean acidification and leaks from proposed CO2 CCS sites. Some of the crabs in the lower pH treatments exhibited a recovery in their responses by day 60, possibly indicating an acclimation effect. The presence of disruption to haemolymph ion concentrations in both the short and longer term hermit crab studies suggest a mechanism for behavioural disruption. In a final study the effects of reduced sea water pH on a more complex behaviour, involving decision making, was investigated. Reduced sea water pH was shown to disrupt the shell assessment and selection behaviour of P. bernhardus affecting its decision making processes, although not all crabs were affected in the same way. The work presented here therefore demonstrates that reduced sea water pH could have disruptive effects upon both information gathering, via chemo-sensory processes, and decision making in intertidal crustaceans. The mechanism responsible is unlikely to be due to changes in the odour molecule, or physical damage to receptor organs. Rather the observed disruptions could be due (a) to ionic changes, causing metabolic depression or interference with neurotransmitter function, or (b) to disruption to chemoreception per se. Such disturbances to key behavioural processes have implications for inter and intraspecific species interactions and population dynamics in the marine environment. Changes in pH are already experienced by intertidal animals for short periods when rock pools are emersed, but future anthropogencially-induced reductions in sea water pH are likely to cause more sustained and widespread disruptions with, as yet, unpredictable consequences. The differential responses observed between individuals in these studies may warrant further investigation as such differences may provide the basis for selection and adaptation to projected changes in ocean pH.
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Watker, A. F. "A study into the alteration of pH through water distribution systems." Thesis, University of Glasgow, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381109.
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Williams, N. L., L. W. Juranek, K. S. Johnson, R. A. Feely, S. C. Riser, L. D. Talley, J. L. Russell, J. L. Sarmiento, and R. Wanninkhof. "Empirical algorithms to estimate water column pH in the Southern Ocean." AMER GEOPHYSICAL UNION, 2016. http://hdl.handle.net/10150/614732.
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Empirical algorithms are developed using high-quality GO-SHIP hydrographic measurements of commonly measured parameters (temperature, salinity, pressure, nitrate, and oxygen) that estimate pH in the Pacific sector of the Southern Ocean. The coefficients of determination, R-2, are 0.98 for pH from nitrate (pH(N)) and 0.97 for pH from oxygen (pH(Ox)) with RMS errors of 0.010 and 0.008, respectively. These algorithms are applied to Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) biogeochemical profiling floats, which include novel sensors (pH, nitrate, oxygen, fluorescence, and backscatter). These algorithms are used to estimate pH on floats with no pH sensors and to validate and adjust pH sensor data from floats with pH sensors. The adjusted float data provide, for the first time, seasonal cycles in surface pH on weekly resolution that range from 0.05 to 0.08 on weekly resolution for the Pacific sector of the Southern Ocean.
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Fürtjes, Theresa [Verfasser], and Stephan [Akademischer Betreuer] Schreml. "Impact of a pH 5 Oil-in-Water (O/W) Emulsion on Skin Surface pH / Theresa Fürtjes ; Betreuer: Stephan Schreml." Regensburg : Universitätsbibliothek Regensburg, 2018. http://d-nb.info/1152437542/34.
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Fürtjes, Theresa Verfasser], and Stephan [Akademischer Betreuer] [Schreml. "Impact of a pH 5 Oil-in-Water (O/W) Emulsion on Skin Surface pH / Theresa Fürtjes ; Betreuer: Stephan Schreml." Regensburg : Universitätsbibliothek Regensburg, 2018. http://nbn-resolving.de/urn:nbn:de:bvb:355-epub-367214.
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Grant, Annie, and Ingrid Luffman. "IS WATER QUALITY IN BOONE LAKE A DAM PROBLEM? AN ASSESSMENT OF WATER QUALITY PRE- AND POST- DRAWDOWN." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/115.
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Boone Lake was formed in 1952 by the impoundment of the South Fork Holston River in Sullivan and Washington counties, TN. The “V” shaped lake spans 6.88 square miles; it consists of two primary tributaries of approximately equal-length which meet just above the dam. South Fork Holston River makes up the northern arm and Watauga River feeds the southern arm. In October 2014, the discovery of a sinkhole led to detection of sediment-laden seepage under the earthen part of the dam. As a safety precaution, the reservoir was immediately lowered to an elevation of 1,352.5 feet, 10 feet below operational “winter” levels. It will remain there until the anticipated dam repair completion date of 2022. This study compares reservoir water quality data collected before seepage detection to data collected since drawdown to determine the impact of drawdown on water quality in the reservoir. Parameters analyzed were Dissolved Oxygen (DO), turbidity, conductivity (EC), Total Dissolved Solids (TDS), pH, temperature, and Escherichia Coli (E. coli). Data were compiled from two sources consisting of samples taken from 22 locations dispersed throughout each arm of the reservoir. Statistical analysis of pre/post-drawdown data was conducted using independent samples t-tests and Mann-Whitney tests as appropriate. Results of this study indicate water quality in Boone Lake has changed significantly since water levels were lowered. This change is likely due to flushing of the reservoir caused by ongoing dam repair. Conductivity, TDS, and E. coli levels have decreased significantly, suggesting improvements in water quality. Changes in temperature and pH were also found to be significant. Time series analysis of temperature and pH show significant trends overtime suggesting the lake will continue to warm and acidify. This combination of changes could negatively impact water quality, as metals trapped in lake sediments will likely become increasingly mobilized. Based on these findings, it is recommended that water quality data be collected regularly at consistent time intervals using a paired samples approach throughout the completion of the dam’s repair and continuing thereafter. Additionally, based on pH and temperature findings, it is recommended that water quality testing include testing for presence and concentrations of metals to stay vigilant to potential changes in the water column.
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Ye, Xuemin. "The effect of water pH on swimming performance, blood pH, red cell pH, ion concentrations and catecholamine concentrations in plasma, and gill potential in rainbow trout (Salmo gairdneri)." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26676.
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The effect of transferring fish from water at pH 7.0 to either more acid or more alkaline conditions was to reduce the maximum critical velocity of the fish. In water of pH 4.0, 5.0, and 10.0, the maximum critical velocity was only 54.5%, 66.5%, and 61% respectively of that recorded for fish in the water of pH 7.0. Thus, both acid and alkaline conditions in the water reduce the aerobic swimming capacity of trout.
Exposure to acid conditions increased mucus secretion and this was associated with an increase in coughing and breathing frequency in resting fish. Coughing rate increased from 41/hr to 592/hr; and respiration frequency increased from 81/min to 104/min when fish were transferred from water at pH 7.0 to water at pH 4.0.
In comparing fish exposed to acid and alkaline waters, the results indicates that fish have a greater capacity to regulate blood pH in acid than in alkaline conditions.
The gill potential was strongly dependent on water pH, being negative in neutral water, but positive in acid water and more negative in alkaline solution. Catecholamine levels increased significantly during acid exposure, but were not altered during alkaline exposure. The increasing catecholamine levels appeared at different time periods in different fish during acid exposure and seemed to be associated with the death of the fish.
Na⁺ and C1⁻ ion concentrations in plasma decreased significantly after 24hrs of acid exposure, but did not change significantly in alkaline water. This may indicate that ionoregulatory disturbance in plasma is one of the reasons for the decrease in the maximum critical velocity in acid water, but not in alkaline water.Science, Faculty of
Zoology, Department of
Graduate
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Al-Ayed, M. I. M. "Studies on the effects of pH, aluminium and water hardness on Asellus aquaticus." Thesis, Swansea University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.635656.
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In the present study, the interactive effects of Al3+, Ca++ and pH on adult Asellus aquaticus (L.) were investigated. These animals were selected because of their possible usefulness as an indicator species. Results confirmed that there is a higher mortality and death occurs more rapidly at lower pH values. The effects of aluminium on longevity in A. aquaticus were investigated at two temperatures; generally, they survived less well at 18°C than at 11°C. Al3+ had a noticeable effect on oxygen consumption in test specimens and acclimation to Al3+ solutions proved to have considerable influence on this. The range of concentrations of Ca++ provided a protective effect against aluminium toxicity.
12
Miller, Stephanie A. "Investigation of Lead Solubility and Orthophosphate Addition in High pH Low DIC Water." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406821208.
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Obut, Salih. "Control Of Ph In Neutralization Reactor Of A Waste Water Treatment System Using Identification Reactor." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606395/index.pdf.
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A typical wastewater effluent of a chemical process can contain several strong acids/bases, weak acids/bases as well as their salts. They must be neutralized before being discharged to the environment in order to protect aquatic life and human welfare. However, neutralization process is highly non&ndashlinear and has time&ndash
varying characteristics. Therefore, the control of pH is a challenging problem where advanced control strategies are often considered. In this study, the aim is to design a pH control system that will be capable of controlling the pH-value of a plant waste-water effluent stream having unknown acids with unknown concentrations using an on&ndash
line identification procedure. A Model Predictive Controller, MPC, and a Fuzzy Logic Controller, FLC, are designed and used in a laboratory scale pH neutralization system. The characteristic of the upstream flow is obtained by a small identification reactor which has ten times faster dynamics and which is working parallel to actual neutralization tank. In the control strategy, steady&ndash
state titration curve of the process stream is obtained using the data collected in terms of pH value from the response of the identification reactor to a pulse input in base flow rate and using the simulated response of the identification reactor for the same input. After obtaining the steady&ndash
state titration curve, it is used in the design of a Proportional&ndash
Integral, PI, and of an Adaptive Model Predictive Controller, AMPC. On the other hand, identification reactor is not used in the FLC scheme. The performances of the designed controllers are tested mainly for disturbance rejection, set&ndash
point tracking and robustness issues theoretically and experimentally. The superiority of the FLC is verified.
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Lonergan, Sean P. "Macroinvertebrate community responses to acidification : isolating the effects of pH from other water chemistry variables." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68205.
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The effect of lake acidification was evaluated, in the field, in terms of its impact on both the structural and functional composition of the macrozoobenthic community. The littoral macrozoobenthic community and water chemistry of 45 Canadian Shield lakes was sampled. The water chemistry variables sampled included pH, total dissolved calcium, conductivity, and dissolved organic acid (measured as colour). Partial canonical correlation analysis and partial regression analysis were used to identify those components of the macrozoobenthic community that most directly reflected pH variability. This was done by first removing from the data that portion of the variability attributable to total dissolved calcium, conductivity, and dissolved organic acids. In addition, the spatial structure in the data was removed by identifying the geographic coordinates of the sampling sites.In general, the results presented here are not consistent with previous studies where the response of the macrozoobenthic community was related to pH without consideration of confounding covariables. Snails, leeches, mayflies and crayfish have all been cited for their sensitivity to acidification. The present study found these taxa to reflect, not pH variability, but rather attributes of water hardness. Similar results were found for both total zoobenthic biomass and functional feeding group abundance.
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Dobranskyte, Agne. "Bioavailability and toxicity of aluminium in the fresh water snail 'Lymnaea stagnalis' at neutral pH." Thesis, University of Manchester, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488400.
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Baker, Beverly Eloise. "Effect of Water Column pH and NO3 on Ortho-Phosphate Release Rates from Freshwater Sediments." W&M ScholarWorks, 1989. https://scholarworks.wm.edu/etd/1539617604.
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Enetjärn, Albin. "Temporal och spatial variation för pH och relaterade parametrar i Bastuån, Jämtland." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-153162.
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Anthropogenic emissions of acidifying substances, mainly sulfur dioxide, during the second half of the 20th century caused a widespread acidification of many European freshwater environments. Even relatively remote areas, such as inland northern Sweden, experienced reduced pH-values, much due to low buffering capacity in the environment. Extensive liming has taken place in Sweden over the past fifty years to counteract negative effects on limnic ecosystems. Despite a general increase in pH over the last decades, problems with acidification still occur. However, this can be hard to separate from natural acidity due to a large landscape variability. This study aims at describing the temporal and spatial variation of pH and pH-related parameters in Bastuån, a 46 km2 watershed in Jämtland, Sweden, which is being investigated for future liming measures. Existing water chemistry data sets were analyzed and extended with an additional field study, sampling the twelve largest tributaries to Bastuån. Results show that pronounced high and low pH values has become increasingly rare while the average is basically unchanged between 1999 and 2017. Low pH is mainly associated with high discharge during snowmelt or rain events. Anthropogenic SO42- concentrations seems to contribute relatively little to pH-depressions while organic acids plays a more important role. Large water chemical variations in the tributaries indicate that several different biological and physical properties within the watershed regulates pH. However, any credible function that can predict pH using such properties remains to be found.
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Köhler, Stephan. "Quantifying the role of natural organic acids on pH and buffering in Swedish surface waters /." Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5626-6.pdf.
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Wilson, Christopher Brant. "Measurement of chemical composition and pH profiles near the liquid-vapor interface of aqueous solutions using a unique confocal microscope system /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/9840.
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Kumai, Yusuke. "Mechanisms of Na+ Homeostasis by Zebrafish (Danio Rerio) in Acidic Water." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/26205.
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Zebrafish, Danio rerio, are able to survive exposure to extreme acidity (pH 4). Because previous studies demonstrated that disruption of ionic balance during exposure to acidic water is the major cause of mortality in acid-sensitive freshwater species, the focus of this thesis was to characterize the molecular mechanisms enabling zebrafish to maintain their Na+ homeostasis following exposure to acidic water. Initial findings (Chapter 2) demonstrated that branchial mRNA expression of selected isoforms of claudins, major components of tight junctions, are altered in an isoform-dependent manner, suggesting the potential regulation of epithelial permeability to minimize ion loss. Concurrently, a marked stimulation of Na+ uptake was observed in adults and larvae following acid-exposure. Because of the uniqueness of this response (increasing Na+ uptake in acidic water) among freshwater teleosts, the mechanisms related to Na+ uptake and its stimulation were investigated further (Chapters 3 - 7). Pharmacological treatments and gene knockdown approaches revealed that a functional metabolon consisting of an apically expressed Na+-H+-exchanger (NHE3b) in association with an apically expressed ammonia-conducting channel (Rhcg1), enables Na+ uptake in acidic water.
During chronic (>1 day) exposure to acidic water, cortisol (via glucocorticoid receptors) and catecholamines (via β-adrenergic receptors) are involved in stimulating Na+ uptake. Although catecholamines may act on both NHE3b and Na+-Cl- co-transporter (NCC), the effects of cortisol on Na+ uptake are mediated primarily by activation of NHE3b. On the other hand, during acute (<3 h) exposure to acidic water, cortisol does not appear to affect Na+ uptake; rather, the stimulation of Na+ uptake appears to be mediated by angiotensin II and catecholamines. Cyclic AMP (cAMP), a signalling molecule synthesized following the activation of β-adrenergic receptors, is critically involved in stimulating Na+ uptake, likely via activation of NHE3b and NCC. In agreement with this idea, ionocytes that express NHE3b also express high levels of β-adrenergic receptor (propranolol binding sites) as well as trans-membrane adenylyl cyclase (forskolin binding sites).
Taken together, the results of this thesis provide fresh insight into the mechanisms of osmoregulation in freshwater (FW) fish. In particular, the data reveal the presence of complex pathways regulating Na+ uptake in zebrafish exposed to acidic water. The relative importance of the various pathways depends in part on the duration of exposure; acute versus chronic.
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Evans, C. E. "Effect of soil and water potential and pH on germination and establishment of some British plants." Thesis, Bucks New University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374822.
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Wallace, Ashley J. "pH-triggered Self-Assembly of a PEGylated Peptide Amphiphilic Contrast Agent." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500485484867638.
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Yang, Teng Teng, and 杨婷婷. "Corals in a variable physical environment : impacts on growth and the [delta]¹¹B pH-proxy." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/209621.
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Coral reefs are important to sustain marine ecosystems and provide a reliable resource for studying past climate. Corals are increasingly challenged by changing environments. The marginal corals of Hong Kong provide a natural laboratory to study the combination of environmental conditions controlling coral distribution and growth. Salinity and pH were found to impact corals in studies of coral distribution, extension, and culture. Hong Kong corals have low extension rates (1.2-11.4 mm/yr) and do not colonize in areas of low in salinity and pH. Ten years of instrumental records showed extension related positively to summer salinity and dissolved oxygen. Winter seawater temperature was inversely related to extension, while chlorophyll a showed positive relationship in autumn and winter. Culture results show low salinity negatively impacted coral calcification, photosynthesis, and extension. Corals exhibited reduced growth, paling and bleached. In contrast, coral growth increased under high pCO2, but corals decalcified in dark indicating underlying mechanisms may be altering coral physiology.
The boron isotope (δ11B) proxy in corals is able to reconstruct past seawater pH when the pH of the extracellular calcifying fluid (ECF) is considered. A pH offset (ΔpH) was recorded in reconstructed pHsw due to ion pumping to ensure the ECF is saturated with respect to aragonite. By incorporating carbon isotopes (δ13C) into the δ11B-ΔpH relationship, δ11B can be corrected to remove ECF processes and reconstruct seawater pH. Culture results indicated δ11Baxial from axial tip recorded pH similar to other studies while low salinity impacted δ11Bbasal at the base. The different relationship shown from the same colony within the same cultured conditions suggested vital effects with differing coral metabolisms. δ11Baxial and δ11Bbasal related to extension but insignificantly. The large isotopic offset between δ11Baxial and δ11Bbasal indicated different growth mechanisms could possibly affected boron incorporation. The δ11B variation within a coral colony suggested careful and precise sampling for pH reconstructions is important.published_or_final_version
Earth Sciences
Doctoral
Doctor of Philosophy
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Moldan, Filip. "Reversal of soil and water acidification in SW Sweden : simulating the recovery process /." Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5851-X.pdf.
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Bezděk, Ondřej. "Vliv pH záměsové vody na hydrataci a mechanické vlastnosti cementových kompozitů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2015. http://www.nusl.cz/ntk/nusl-217110.
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This master’s thesis is focused on the effect of mixing water pH value on hydration and mechanical properties of cement composites based on portland cement. Source material was CEM I 42,5 R. Hydration process was analyzed by isoperibolic calorimetry, X-ray diffraction analysis and differential thermal analysis. Compressive and flexural strength was examined as mechanical properties. The samples microstructure was observed by scanning electron microscopy. Influence of mixing water pH value on flexural and compressive strength, retardation of hydration and ratio of individual phases was shown.
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Zhang, Zhenyu. "Mechanical properties and pH-dependent conformation of a model polymer and biomolecule at the silica-water interface." Thesis, University of Sheffield, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489101.
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This thesis is concerned with the mechanical properties and pH-dependent conformation of macromolecules at the silica-water interface. It is believed that the adhesion of bacteria to solids is governed by long-range interactions and by immediate interactions between bacterial surface polymers and solid surfaces. For a flexible macromolecule, the interaction of its segments with a solid surface and the conformation it takes at the interface are prominent factors in determining the net interaction to solids.
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MAGINNIS, ALEXANDER R. "THE USE OF MICROELECTRODES FOR THE MEASUREMENT OF pH AND DO AT THE WALL OF DRINKING WATER PIPES." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin998062134.
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Schulte-Herbruggen, Helfrid Maria Albertina. "Remote community drinking water supply : mechanisms of uranium retention and adsorption by ultrafiltration, nanofiltration and reverse osmosis." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/7716.
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Worldwide, around 884 million people lack access to safe drinking water. To address this, groundwater sources such as boreholes and wells are often installed in remote locations especially in developing countries. However, the natural chemical composition of groundwater may be a source of toxicity to human health. Uranium is naturally present in the environment, and concentrations above the World Health Organisation (WHO) drinking water guideline (15 μg/L) are found in various parts of the world. Uranium has a complex aqueous chemistry and its speciation, which varies according to pH and available ligands, determines its behaviour (e.g. mobility, reactivity or sorption tendency). Nanofiltration and reverse osmosis have proved effective in removing uranium from water, although fundamental removal mechanisms are not well understood. Even the more porous ultrafiltration (UF) has been shown to remove uranium when used in combination with complexation/coagulation methods. To address the water purification needs of remotely located communities with no or unreliable access to energy, a renewable energy powered membrane system was designed using UF as pre-treatment to remove particles, bacteria and viruses and NF/RO to remove ions. The system was trialled in the Australian outback, using natural groundwater high in uranium (>300 μg/L). Results showed that pH had a large effect on the uranium behaviour in the system and, curiously, interaction by sorption or precipitation to the membranes was observed at certain pH values. However, due to the complexity of the water and the combination of UF and NF/RO membranes, the mechanisms of the uranium retention and interaction with the membrane were not clear. Further systematic study was needed to investigate the uranium behaviour with the membranes. Laboratory studies were carried out with one membrane type at a time: UF, NF and RO. It was postulated that pH, organic matter and inorganic ions such as calcium have an important influence on uranium retention and interaction with membranes. Results show that uranium behaviour in the membrane systems was highly pH dependent. During the UF experiments, increased adsorption of uranium occurred in uranium-only solutions at pH 5-7. From the UF experiments with organic matter it could be concluded that organic matter did not increase retention (size exclusion) of uranium, however it did increase the adsorption. Humic acid increased adsorption to 80-95% at pH 3-5, alginic acid at pH 3 while tannic acid caused a nearly 100% adsorption at pH 10-11. Further investigating uranium behaviour with NF and RO membranes, it was found that uranium showed the same increase in affinity to the membrane at pH 5-7, with about 50% being taken up by NF and 30% by RO membranes. The effect of pressure on uranium-membrane interaction was investigated for NF and RO at pH 6 and 8.5. Pressure and consequent concentration polarisation only increased uranium affinity to the NF membrane at pH 8.5 where the uranium species and MWCO of the membrane were similar. There was no or little effect of pressure on the affinity of uranium to the NF membrane at pH 6 or to the RO membrane. At pH 6, STEM-EDX results showed that uranium was distributed through-out the polyamide active layer of the NF membrane while FTIR results confirmed that uranium bound to carboxyl groups in the polyamide. At pH 8.5 however, FTIR results showed that uranium did not form chemical bonds with the membrane, but was rather attracted to the surface through hydrogen bonding and loosely forming a layer on top of the membrane visible in SEM. It was concluded that at least three different characteristics of the uranium species and membranes played a role for the interaction: 1) uranium species valency and membrane charge, 2) uranium species size relative to the membrane pore size, and 3) the reactivity of the uranium species towards the membrane functional groups. The effect of calcium on uranium retention and uranium-membrane interaction in NF and RO was also investigated. Calcium affects uranium speciation by forming a neutral complex with uranium at pH 8-9, causing a decrease in adsorption to the membrane. Calcium also precipitates at pH 10. SEM and TEM images showed that the precipitation of calcium carbonate (CaCO3) as calcite caused co-precipitation of uranium, trapping it on the surface of the membrane. About 48-55% of the calcium precipitated which caused a 26-35% co-precipitation of uranium, compared to <5% adsorption in the absence of calcium at pH 10. Finally the chemical drinking water quality of mainly boreholes and wells across a West African country, Ghana, was investigated (199 samples in total from “improved” sources). In addition, the user water costs were documented and the scope for advanced treatment explored. The WHO guidelines for chemical water quality were exceeded in 38% of the samples. The main contaminants were nitrate (21%), managanese (11%) and fluoride (7%), while heavy metals such as lead, arsenic and uranium were localised to mining areas. It was concluded that when taking the cost of unsuccessful borehole development into account, alternative treatment may be a suitable option where inorganic contamination is high. The findings from this study show the importance of the water quality conditions (pH, organic matter and calcium) on the behaviour of contaminants such as uranium in membrane systems and explain the mechanisms of adsorption and co-precipitation of uranium to the membranes at certain pH values. These are important considerations when selecting appropriate membranes for water treatment and also for the maintenance of membranes. The study also showed that there is need for advanced treatment of drinking water in e.g. Ghana, but highlights the importance of strategies on local and national level to ensure long-term sustainability and integration of any such treatment.
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Pinto, Marinaldo Ferreira. "Desenvolvimento de um sistema para o controle do pH da água para irrigação localizada." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-21062010-154440/.
Full textAbstract:
A obstrução de emissores por causas químicas, em sistemas de irrigação localizada, é um problema crucial enfrentado pelos irrigantes, que em muitos casos, dependendo da gravidade, são obrigados a substituir o sistema existente. Isso se deve à presença de íons específicos, que em determinadas condições precipitam, provocando a obstrução dos emissores e tubulações. No entanto, pode-se intervir nas condições propícias a esse processo, de modo a preveni-lo. Uma forma de intervenção é a injeção de ácido, uma vez que este processo ocorre com maior proporção quando a água de irrigação apresenta valores de pH acima de 7. Neste contexto, objetivou-se com este trabalho desenvolver um dispositivo eletrônico de controle do pH da água para irrigação localizada. O trabalho foi desenvolvido no Laboratório de Hidráulica do Departamento de Engenharia de Biossistemas (LEB) da Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP). O sistema de controle apresenta de um dispositivo de injeção de ácido (atuadores) controlado através de uma válvula solenóide, comandada por pulsos elétricos, enviados pelo processador, que está associado a um circuito de leitura de um sensor, que detecta o pH da água em tempo real. A lógica de controle é baseada na diferença entre as entradas e as saídas do controlador, de modo que, as decisões futuras são baseadas nas respostas proporcionadas pelas ações anteriores. O ciclo de cada ação sobre os atuadores tem uma duração média de 3 s, que compreende o tempo entre 2 leituras consecutivas do pH e injeção de ácido na água. O sistema foi testado em águas de diferentes valores iniciais de pH (variando de 6,2 a 9,2) sob vazão constante (264 L h-1) e variável. Além disso, foi instalada uma linha lateral de irrigação com comprimento de 44 m, composta de microtubos (emissores) espaçados de 1 m, aonde foi verificado os valores de pH da água na saída dos emissores ao longo da linha lateral (início, 1/3, 2/3 e fim) e em diferentes intervalos de tempos a partir do início dos testes. Os resultados obtidos comprovam a eficiência do dispositivo em manter o pH da água na faixa desejada, tanto para a condição de vazão constante, quanto variável. Em relação ao pH da água medido na saída dos emissores, não foi verificado variações significativas, tanto temporal quanto espacial, sempre se mantendo dentro da faixa desejada.The clogging of emitters by chemical causes, in drip irrigation systems, is a crucial problem faced by the irrigators that in many cases, depending of the gravity, are ordered to replace the existent system. This is occurring due to the presence of the specific ions, which it precipitates in determined conditions, causing the clogging of emitters and pipes. However, it can intervene in the conditions for these processes to prevent them. A way of intervention is the acid injection, since this process occurs in major proportion, when the irrigation water shows values of pH above 7. In this context, the aim of this work was to develop an electronic device of control of the pH water for irrigation drip. The work was developed in the Laboratory of Hydraulic of Department of Biossystems Engineering (LEB), at Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP). The system of control shows a device of acid injection (actuators) controlled though a solenoid valve, commended by electrics pulse that it sent by the processor, that is associated with a reading circuit of sensor, that it detects the pH of water in the real time. The logical control is based on the difference between the input and output of controller, so that the future controller decisions are based on answers caused by early actions. The cycle of each action on the actuator has the medium duration of 3 s, that it meaning the time between 2 consecutive reading of pH and acid injection in the water. The system was tested in waters of different values of pH (ranging 6.2 to 9.2) under constant (264 L h-1) and variable flow. Moreover, it was installed a lateral line of irrigation with length of the 44 m, it was composed of microtubes (emitters) spaced 1 m, where it was verified the pH of water in outlet of emitters along of lateral line (begin, 1/3, 2/3 and end) and in different intervals of time after starting of tests. The results obtained proved the efficiency of the device to maintain the water pH in the desired range, for the both conditions, constant as variable flow. In relation to the water pH in the outlet of emitters, it wasnt verified meaningful variations, both temporal and spatial, it always maintained into the desired range.
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Crossley, Mark Norman. "The effects of water flow, pH and nutrition on the growth of the native aquatic plant, Aponogeton elongatus /." [St. Lucia, Qld. : s.n.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17481.pdf.
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Millette, Louise. "The effect of pH adjustment on the internal corrosion rate of cast iron and copper water distribution pipes." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/26316.
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Two experimental sessions were conducted to examine to effects of pH adjustment on internal corrosion of cast iron and copper water distribution pipes. The Greater Vancouver Regional District uses surface lakes as its potable water source. As confirmed by chemical water characteristics monitoring, the supplied tap water has several of the attributes of an aggressive water: low pH (4.9 to 5.7), low alkalinity (10 to 15 mg/L as CaCO₃), low hardness (6 to 7 mg/L as CaCO₃), and dissolved oxygen consistently near saturation.
Because of this aggressive nature, the tap water has a tendency to dissolve water distribution pipes, and in particular domestic copper pipes (municipal cast iron mains are cement lined for corrosion protection). This accelerated corrosion of copper pipes not only increases the maintenance costs for home owners, it also encourages high levels of copper in their tap water. This last finding was confirmed by a preliminary tap water metal concentration survey wherein, after a month of sampling of six dwellings, it was found that the recommended maximum copper level of 1.0 mg/L was exceeded in 67% of the cold water morning first flush samples.
The investigated corrosion control measure consisted of pH adjustment to target values of 6, 7 and 8, through the addition of hydrated lime (Ca(OH)₂). Cast iron and copper pipe samples were exposed to pH adjusted water for durations ranging from one to twelve weeks. For the most part, the adjusted pH experimental flow-through units were gravity-fed; however, to examine the effects of the much higher normal distribution system pressure, another set of control units were maintained at system pressure.
Although it was found that the absolute winter corrosion rates were higher than the summer rates, analysis of the relative coupon weight loss variations, with reference to the gravity control unit, lead to two major findings. The corrosion rates of cast iron were ten times those of copper and the increased pH acted to enhance these cast iron corrosion rates by approximately 15%. However, pH adjustment successfully decreased copper corrosion by 68%. The effects of the increased pressure on corrosion were different for both metals. The corrosion rates of cast iron coupons in the control pressurized cells were twice the rates of the coupons in the gravity control units. The effect of the increased pressure on copper was not as marked, but the rates were found to be slightly lower than expected from the pressurized water lower pH.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Rodrigues, Bruno da Silva. "Projeto e implementação de um sistema matricial para medição de pH baseado em transistores de porta suspensa (SGFET)." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-12122011-132247/.
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Este trabalho tem como objetivos: a caracterização dos sensores SGFET (Suspended Gate Field Effect Transistors) para medidas de pH, o desenvolvimento de um protocolo de calibração destes sensores e o desenvolvimento de um sistema autônomo de medidas utilizando matrizes de sensores SGFET para controle do pH e monitoramento da qualidade de água potável. Diferentes arranjos experimentais e metodologias de testes foram analisados no decorrer do trabalho. Na caracterização do sensor de pH, foram obtidas sensibilidades de até S=449 mV/pH valor 7 vezes superior à sensibilidade máxima obtida em pHmetros de eletrodos combinados que baseiam-se no potencial Nernst (59,15 mV/pH), para medidas de Vgs e S=6 A/pH, para medidas da corrente Ids. Com base nesta caracterização, foram realizados testes para o monitoramento da qualidade de água potável durante um período de 135 horas. As medidas mostraram uma grande estabilidade e reprodutibilidade dos sensores SGFET. Nos testes utilizando o sistema autônomo de medidas, foram obtidas sensibilidades de até S=715 mV/pH. No primeiro capítulo será apresentada uma revisão bibliográfica das características, vantagens e desvantagens dos principais medidores de pH utilizados atualmente. No segundo capítulo apresentamos os princípios de funcionamento dos sensores SGFET utilizando como base transistores de efeito de campo do tipo metal óxido semicondutor (MOS-FET). No terceiro capítulo apresentamos um resumo das etapas de fabricação dos sensores SGFET, onde compararemos dois processos de fabricação. O primeiro processo é referente às etapas de fabricação do transistor SGFET realizadas no grupo de microeletrônica do Institut d\'Electronique et des Télécommunications de Rennes (IETR) na Universidade de Rennes 1 e o segundo processo é referente às etapas de fabricação de transistores SGFET realizada na empresa MHS situada na cidade de Nantes na França. Também introduzimos o conceito de matrizes sensores SGFET. No quarto capítulo serão apresentados os resultados das medidas experimentais dos sensores SGFET, tanto para o uso do dispositivo no controle do pH de soluções aquosas, como no monitoramento de água potável. Também apresentamos o detalhamento do protocolo de calibração desenvolvido para aumentar a reprodutibilidade das medidas. No quinto capítulo serão apresentados os elementos do sistema autônomo de medidas e os resultados iniciais das medidas experimentais realizadas utilizando esse sistema. Também serão apresentadas as vantagens e facilidades que o desenvolvimento desse sistema de medidas agregou aos resultados experimentais. Finalmente no Capítulo Seis as conclusões e no Capítulo 7 as sugestões de trabalhos futuros.The objectives of this work are: the characterization of the and SGFET (Suspended Gate Field Effect Transistors) sensors applied to pH measurements, the development of a calibration protocol of these SGFET sensors and the development of an autonomous measurement system using SGFET sensor matrixes for pH control and drink water quality monitoring. In this work, many experimental arrangements and tests methodologies were analyzed. Sensitivities up to 449 mV/pH, measuring the variation of Vgs, and 6 A/pH, measuring the Ids current were obtained. For drink water quality monitoring, long time test (135 hours) was performed. The sensors showed a high stability and reproducibility. The autonomous measurements system also showed a high sensitivity (up to S = 715 mV/pH). The first chapter shows a review of the characteristics, advantages and disadvantages of the main pH meters used today. In the the second chapter, the SGFET sensor, based on MOS-FET transistor, operating principles will be present. The third chapter is the fabrication steps of SGFET sensors summary, where we compare two processes: the IETR (\"Institut d\'Electronique et de Télécommunications de Rennes\") process, developed at the University of Rennes 1, and the MHS (a private company located in Nantes-France) process. Also, we introduce the SGFET sensors matrixes. In the fourth chapter, it is present the experimental results obtained from the SGFET sensors measurements to pH control and drink water quality monitoring. Also, the details of the calibration protocol, developed to increase the measurements reproducibility, are present. In the fifth chapter, the details of the measurement autonomous system are described as well as the preliminary results are presented. Also, the advantages and the added value of this system gave to the experimental results are showed. Finally, in the sixth chapter, the conclusion of this work are presented and in the seventh chapter some future works are suggested.
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Gatewood, Marena Dessette. "Solubility and recovery of L-isoleucine from high pH solutions and the cause for L-serine habit differences when crystallized from water and methanol/water solutions." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/10916.
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Gorsuch, Valerie A. "Tumble Marination Strategies to Improve pH, Color, and Water-Holding Capacity in Pale, Soft, and Exudative (PSE) Broiler Breast Fillets." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/42374.
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Tumble marination strategies to improve pH, color, and water holding capacity of pale, soft, and exudative (PSE) broiler breast fillets
Valerie A. Gorsuch, M.S.
Virginia Polytechnic Institute and State University
Advisor: Christine Z. Alvarado
ABSTRACT:
Recently, there has been an increase in the incidence of pale soft and exudative poultry meat. Pale, soft, and exudative (PSE) meat is caused by a decline in pH early postmortem while carcass temperatures are still high. This decrease in pH leads to protein denaturation attributing to the pale color and poor water holding capacity (WHC) that is characteristic of this lesser quality meat. Pale, soft, and exudative meat has economic implications for processors with losses ranging between $2-4 million each year. Marination with salt and phosphates has been shown to improve protein functionality, thereby reducing lost meat yield and improving meat color, WHC, and texture. However, there are few studies relating marination with phosphates to improvements in PSE meat. Therefore, the purpose of this study was to determine if color, WHC, and texture improvements could be obtained in PSE meat via marination with various phosphate and NaCl treatments without altering the quality and oxidative stability of normal or PSE meat. In Experiment 1, 12 phosphates were evaluated for improvements in pH, color, and WHC of PSE meat. From these, five phosphates were chosen based on pH, color, and WHC improvements for Experiment 2. The marinades used in Experiment 2 increased the pH, decreased the L* values of the pale fillets, and improved water holding capacity. Thiobarbituric acid-reactive substances, sensory, and microbial analysis studies concluded that marination with high pH phosphates can reduce the undesirable characteristics of PSE meat without increasing the development of oxidation, altering flavor, or reducing shelf-life.Master of Science
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Sjöholm, Johannes. "Trapping Tyrosine Z : Exploring the Relay between Photochemistry and Water Oxidation in Photosystem II." Doctoral thesis, Uppsala universitet, Molekylär biomimetik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-173575.
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Photosystem II is unique! It remains the only enzyme that can oxidize water using light as energy input. Water oxidation in photosystem II is catalyzed by the CaMn4 cluster. The electrons extracted from the CaMn4 cluster are transferred to P680+ via the tyrosine residue D1-Tyr161 (YZ). Favorable oxidation of YZ is coupled to a proton transfer along a hydrogen bond to the nearby D1-His190 residue, resulting in the neutral radical YZ•. By illuminating photosystem II at cryogenic temperatures, YZ• can be trapped in a stable state. Magnetic interaction between this radical and the CaMn4 cluster gives rise to a split electron paramagnetic resonance (EPR) signal with characteristics that depend on the oxidation state (S state) of the cluster. The mechanism by which the split EPR signals are formed is different depending on the S state. In the S0 and S1 states, split signal induction proceeds via a P680+-centered mechanism, whereas in the S2 and S3 states, our results show that split induction stems from a Mn-centered mechanism. This S state-dependent pattern of split EPR signal induction can be correlated to the charge of the CaMn4 cluster in the S state in question and has prompted us to propose a general model for the induction mechanism across the different S states. At the heart of this model is the stability or otherwise of the YZ•–(D1-His190)+ pair during cryogenic illumination. The model is closely related to the sequence of electron and proton transfers from the cluster during the S cycle. Furthermore, the important hydrogen bond between YZ and D1-His190 has been investigated by following the split EPR signal formation in the different S states as a function of pH. All split EPR signals investigated decrease in intensity with a pKa of ~4-5. This pKa can be correlated to a titration event that disrupts the essential hydrogen bond, possibly by a direct protonation of D1-His190. This has important consequences for the function of the CaMn4 cluster as this critical YZ–D1-His190 hydrogen bond steers a multitude of reactions at the cluster.
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Arora, Jaideep. "Effect of formulation and pH on rheological properties, particle size distribution, and stability of oil-in-water beverage emulsions." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86952.
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Beverage emulsions are oil-in-water (o/w) emulsions prepared by dispensing vegetable oils in an aqueous base containing hydrocolloids, preservatives, acid and colors. Stability of such emulsions, in both concentrated forms and diluted final preparations, is a requirement and physical separation (creaming) is a critical problem in the beverage industry. The main objective of this research was to investigate the concentration effects of different hydrocolloids, both individually and in combinations, at two pH levels (neutral and 3.4) on the associated rheological properties, particle size distribution, and stability of prepared o/w emulsions and determine optimal conditions for their stability in both concentrated (2 weeks) and diluted forms (2 months).Oil-in-water emulsions were made using gelatins (Types "A" and "B"), modified starch and modified Arabic gum alone and with selected viscosity builders (Xanthan gum and propylene glycol alginate), and their rheological properties, and their physico-chemical properties were evaluated. Emulsions demonstrating reasonable stability were selected and incorporated into a simulated juice base and a mimicked dairy beverage. Creaming behavior and stability of simulated beverages, containing 2% emulsion, were evaluated over a storage period of 2 months.
Viscous and elastic properties of the concentrated emulsions as well as their opacity increased with an increase in hydrocolloid concentration. Gelatin type 'A' at neutral pH and type 'B' at pH 3.4 was less stable possibly due to protein aggregation close to their iso-electric points and loss of repulsive force. Modified starch had a smaller average particle size and possessed suitable stability at both pH levels. Modified gum Arabic was more stable at neutral pH. In simulated beverages, those containing modified starch, modified gum Arabic, type 'A' gelatin-modified starch conjugates exhibited stability with no signs of creaming with thermal and high pressure pasteurization. Obtained results provide useful information for the preparation of novel stable juice and milk beverages, without the historically employed weighting agents (brominated vegetable oil, ester gum, sucrose acetate isobutyrate) for stabilizing beverages.
Les émulsions de boissons huile/eau (o/w) sont préparées en distribuant les huiles végétales dans une base aqueuse contenant des hydrocolloïdes, des agents des agents de conservation, l'acide et des couleurs. La stabilité de telles émulsions, sous les formes concentrées et diluées, est exigent et la séparation physique (écrémage) est un problème critique se posant aux industries des boissons. L'objectif principal de cette recherche était d'étudier les effets de concentration de différents hydrocolloïdes, individuellement et en conjugaisons, à deux niveaux de pH (neutre et 3.4) sur les propriétés rhéologiques, la distribution de dimension particulaire, et la stabilité associées des émulsions huile/eau (o/w) et déterminer des conditions appropriées pour leur stabilité en formes des concentrées et diluées. fr
Des émulsions huile dans eau ont préparé en utilisant les gélatines (types 'A', et 'B'), l'amidon modifié et la gomme acacia modifié seule et avec les modificateur de viscosité (gomme de xanthane et alginate de propylène glycol). Des propriétés mécaniques et physiques des émulsions préparées ont été évaluées. Les émulsions démontré la stabilité raisonnable, ont été choisies et incorporées aux boissons simulées de jus et de lait. Écrémant et la stabilité des boissons simulées, contenant l'émulsion de 2%, ont été évaluées pendant le stockage de 2 mois. Les propriétés visqueuses et élastiques des émulsions concentrées aussi bien que leur opacité ont augmenté avec une augmentation de concentration hydrocolloïde. Le type de gélatine 'A' au pH neutre et le type 'B' à pH 3.4 étaient moins stables probablement à cause de l'agrégation de protéine (près de leurs points isoélectriques) et perte de force répulsive. L'amidon modifié a eu plus petite taille de particule et une stabilité appropriée possédée aux deux niveaux de pH. La gomme acacia modifiée était plus stable au pH neutre. En boissons simulées, ceux contenant l'amidon modifié, gomme acacia modifiée, gélatine type 'A', conjugues de d'amidon modifiés ont demontré une illustrées stabilité raisonnable et sans des signes de l'écrémage. Les résultats obtenus fournissent des informations utiles pour la préparation des émulsions o/w stables (émulsions de boisson) sans addition des agents de poids réglées (e.g. huile végétale bromée, résine estérifiée, isobutyrate d'acétate de sucrose). fr
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De, Luca Antonella. "Fenton and Photo-Fenton like at neutral pH for the removal of emerging contaminants in water and wastewater effluents." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/399786.
Full textAbstract:
In the last decades, the scientific community has been involved in the research of new kinds of contaminants generally known as of “emerging concern” (CECs). The harmfulness of CECs, even at small concentrations as well as, property of bioaccumulation and persistence, makes them extremely dangerous for the human health. The scientific community is constantly researching about novel treatments able to achieve the removal of these contaminants.
Advanced Oxidation Processes (AOPs) are considered one of the most useful treatments to achieve CECs degradation. Among the AOPs, Fenton and photo‐Fenton processes are particularly powerful, cheap and easily managed. Nevertheless, some setting requirements of Fenton processes have limited their application at industrial scale. One of the most important limits is the necessity to operate a tight control of the pH in order to avoid iron precipitation (optimum pH~2.8). Unfortunately, the optimum pH for Fenton reaction is essentially far from the normal values of the wastewater treatment plant (WWTP) effluents. Scientific community is then working on the improvement of the operating conditions of Fenton processes in order to improve the applicability in wastewater treatment. These modifications are essentially focused on the possibility to perform the treatment at circumneutral pH (Fenton and photo‐ Fenton like processes). Fenton like processes can be carried out in heterogeneous or homogeneous way according to the phase of the catalyst into the solution.
In this study was firstly confirmed the suitability of Fenton based processes in recalcitrant compounds removal. Fenton, UV‐A photo‐Fenton and UV‐C photo‐Fenton were, in fact, applied for atrazine removal from secondary effluent (SE) of municipal wastewater treatment plant (MWWTP). UV‐A and UV‐C photo‐Fenton allowed remove 50% and 100% of the initial atrazine content respectively.
The main objective of this thesis was then the assessment of photo‐Fenton’s suitability for recalcitrant contaminant at circumneutral pH. Thus, homogeneous photo‐Fenton like at neutral pH was applied for sulfamethoxazole (SMX) removal. In order to avoid iron precipitation, chelating agents were used to keep soluble the iron at circumneutral pH. The chelating ability of four chelating agents (ethylenediaminetetraacetic acid‐EDTA, nitrilotriacetic acid‐NTA, oxalic acid and tartaric acid) was tested. Then, once determined the optimum molar ratio L:Fe for iron chelation (1.5:1 for EDTA and NTA, 10:1 for tartaric acid and 20:1 for oxalic acid), their catalytic activity was evaluated when employed in photo‐Fenton like for SMX removal. The highest SMX percentage removal, together with the minimum chelating agents required and the better property of biodegradability and low toxicity, demonstrated the suitability of NTA for the purpose.
A further study on the stability of the chelates under reaction was carried out. The operating conditions adopted for the treatment significantly influence the stability of the chelate solution. Thus, in order to proper control the parameter set up the behavior of chelates has been study under thermal, oxidative and photochemical stress. It was demonstrated as the temperature control can represent an interesting tool to extend the chelates lifetime under oxidative and photochemical stress. By adopting different H2O2 doses, a linear correlation between doses and chelate decomposition could be identified. The better suitability of UV‐A irradiation, against UV‐C and Xe lamp, to preserve the iron chelate solution was demonstrated.
Moreover, the influence of the influent characteristics on the process efficiency needed to be also considered. Thus, different water matrices were used for the experiments. The efficiency of photo‐Fenton like catalyzed by Fe(III)‐NTA has been compared when applied to different aqueous matrixes (Milli‐Q water, tap water, secondary effluent wastewater and well water). It was demonstrated as the ions content, especially Ca2+ and Mg2+, significantly compromise the process of chelation. High alkalinities and organic matter, instead, mainly influenced the phase of process, when acting as radicals scavengers, reduced the amount available for SMX oxidation. Some strategies were then adopted to promote SMX removal. Between them, Mn2+ mediated photo‐Fenton like showed somehow possibility for improvement. Highest removal rate was in fact exhibited in the first minutes of reaction when adding Mn2+ to the solution in ratio molar Mn:Fe 0.5:1.
The conclusive study of the thesis regarded the assessment of the Br‐ presence on the efficiency achievable in recalcitrant compounds removal when applying UV/PS/Fe2+ for removal of benzophenone‐4 (BZ4), nitrobenzene (NB), nitrobenzoic acid (NBA), atrazine (ATZ) and ampicilline (AMP). Br‐ demostrated to be a strong inhibitor in the removal of all the considered contaminants except for NB when, the removal was instead enhanced in bromide containing water.
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Payne, Joshua Bill. "Modeling the Growth and Death Kinetics of Salmonella in Poultry Litter as a Function of pH and Water Activity." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-07142005-161524/.
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In order to assess Salmonella dynamics in a poultry production setting, two studies were conducted to evaluate how common environmental factors during production influence Salmonella populations in poultry litter. A field study was initially conducted to determine Salmonella prevalence, populations, serotypes, and antibiotic resistance in fresh excreta and litter from commercial North Carolina broiler farms. Litter pH, temperature, ammonia levels, moisture content, and water activity (Aw) were also measured. The purpose of this field study was to assess the populations and prevalence of Salmonella present during grow-out along with how varying environmental growth parameters and management practices impact its growth, persistence and true risk for consumers. Field data were subsequently used to design a laboratory study that observed the combined effects of pH and Aw at a constant temperature on the growth and decline of Salmonella spp. in inoculated litter for the purpose of predicting microbial behavior using statistical modeling. By understanding the growth and death kinetics of Salmonella based on environmental factors found normally during poultry production, production management strategies can be developed to reduce Salmonella populations on birds entering processing plants, thereby reducing the risk of foodborne illness for consumers.
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Everall, N. C. "The effects of water hardness and pH upon the toxicity of zinc to the brown trout Salmo trutta L." Thesis, Nottingham Trent University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374973.
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加藤, 喜久雄, Kikuo KATO, 錦平 一柳, and Kimpei ICHIYANAGI. "森林流域における酸素安定同位体組成と主要成分濃度の変化について." 名古屋大学農学部付属演習林, 1996. http://hdl.handle.net/2237/8713.
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Lima, F?bio Ara?jo de. "Sistema automatizado para o aproveitamento de ?gua cinza e azul, com controle de PH utilizando l?gica fuzzy." Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15366.
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Previous issue date: 2011-08-31Every day, water scarcity becomes a more serious problem and, directly affects global society. Studies are directed in order to raise awareness of the rational use of this natural asset that is essential to our survival. Only 0.007% of the water available in the world have easy access and can be consumed by humans, it can be found in rivers, lakes, etc... To better take advantage of the water used in homes and small businesses, reuse projects are often implemented, resulting in savings for customers of water utilities. The reuse projects involve several areas of engineering, like Environmental, Chemical, Electrical and Computer Engineering. The last two are responsible for the control of the process, which aims to make gray water (soapy water), and clear blue water (rain water), ideal for consumption, or for use in watering gardens, flushing, among others applications. Water has several features that should be taken into consideration when it comes to working its reuse. Some of the features are, turbidity, temperature, electrical conductivity and, pH. In this document there is a proposal to control the pH (potential Hydrogen) through a microcontroller, using the fuzzy logic as strategy of control. The controller was developed in the fuzzy toolbox of Matlab?
A cada dia a escassez de ?gua se torna um problema mais grave e que atinge diretamente a sociedade mundial. Estudos s?o dirigidos no intuito de conscientizar a popula??o do uso racional desse bem natural que ? imprescind?vel ? sobreviv?ncia. Somente 0,007% das ?guas dispon?veis no globo apresentam acesso f?cil e podem ser consumidas por seres humanos, sendo encontradas em rios, lagos, etc. Para melhor proveito das ?guas utilizadas em resid?ncias e pequenos estabelecimentos, projetos de reuso s?o muitas vezes implementados, implicando, em economia para os clientes das concession?rias de ?gua. Os projetos de reuso envolvem as mais diversas ?reas da engenharia, podendo ser citadas a Engenharia Ambiental, Engenharia Qu?mica e tamb?m a Engenharia El?trica e de Computa??o, essas ?ltimas, respons?veis pelo controle dos processos, que tem por objetivo tornar a ?gua cinza, ou seja, ?guas com sab?o e ?guas azuis, mais conhecidas como ?guas de chuva, ideais para o consumo, ou apenas para utiliza??o em regas de jardins, descargas sanit?rias, entre outros. A ?gua possui v?rias caracter?sticas que devem ser levadas em considera??o, em se tratando do seu reuso. Algumas delas s?o, turbidez, temperatura, condutividade el?trica, pH. Nesse documento ? feita uma proposta de controle de pH (potencial hidrogeni?nico), atrav?s de microcontrolador, utilizando-se como estrat?gia de controle a l?gica fuzzy. O controlador foi desenvolvido no toolbox fuzzy do software Matlab?
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Lunden, James J. "Ocean Acidification and the Cold-Water Coral Lophelia pertusa in the Gulf of Mexico." Diss., Temple University Libraries, 2013. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/230387.
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BiologyPh.D.
Ocean acidification is the reduction in seawater pH due to the absorption of anthropogenic carbon dioxide by the oceans. Reductions in seawater pH can inhibit the precipitation of aragonite, a calcium carbonate mineral used by marine calcifiers such as corals. Lophelia pertusa is a cold-water coral that forms large reef structures which enhance local biodiversity on the seafloor, and is found commonly from 300-600 meters on hard substrata in the Gulf of Mexico. The present study sought to investigate the potential impacts of ocean acidification on L. pertusa in the Gulf of Mexico through combined field and laboratory analyses. A field component characterized the carbonate chemistry of L. pertusa habitats in the Gulf of Mexico, an important step in establishing a baseline from which future changes in seawater pH can be measured, in addition to collecting in situ data for the design and execution of perturbation experiments in the laboratory. A series of recirculating aquaria were designed and constructed for the present study, and support the maintenance and experimentation of live L. pertusa in the laboratory. Finally, experiments testing L. pertusa's mortality and growth responses to ocean acidification were conducted in the laboratory, which identified thresholds for calcification and a range of sensitivities to ocean acidification by individual genotype. The results of this study permit the monitoring of ongoing ocean acidification in the deep Gulf of Mexico, and show that ocean acidfication's impacts may not be consistent across individuals within populations of L. pertusa.
Temple University--Theses
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Nikzad, Nadia. "Optimisation of a small-scale ultrafiltration system for separation of humic substances from surface water." Thesis, KTH, Kemiteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298358.
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Norrvatten är den fjärde största dricksvattenproducenten i Sverige. De producerar och distribuerar dricksvatten till 14 kommuner norr om Stockholm. Norrvatten har under en tid studerat alternativa processer för att optimera och öka produktionskapaciteten och effektiviteten i deras dricksvattenreningsverk vid Görvälnverket. I detta projekt har en pilotanläggning använts för att studera och optimera ett hybridprocessteg bestående av ett koagulerings- och ultrafiltreringssteg med syfte att avlägsna humusämnen från ytvatten. Effekten av pH, reaktionstid och olika matarvattenkvaliteter (Görväln, Fyrisån och sandfiltrat) analyserades genom en serie experiment utförda med pilotanläggningen. Den mest optimala placeringen av ett eventuellt ultrafiltreringssteg i reningsprocessen studerades även. Resultaten från experimenten påvisade att pH mellan 6.1 och 6.7 inte hade någon effekt på reningen av fDOM. Mer signifikanta skillnader i rening kunde observeras mellan de olika koaguleringsdoserna, vilket indikerar att denna parameter är viktigare än pH. Reaktionstiden hade ingen märkbar effekt på anläggningens reningseffektivitet. Däremot ökade transmembrantrycket tio gånger snabbare under experimenten med den kortare reaktionstiden. Dessa resultat antyder att de bildade flocken var mindre och därmed blev mer tätt packade i ultrafiltret vilket i sin tur lett till det snabbt ökande trycket i membranet. En avskiljning av minst 50 %, men inte mer än 60 %, av det ingående fDOM kunde uppnås med alla matarvatten utom sandfiltratet, som hade en reningseffektivitet på 18 %. Vattnet från Fyrisån visade sig vara en utmaning för anläggningen att hantera, då trycket snabbt byggdes upp i membranet vilket tyder på att anläggningen inte klarar för starkt förorenade vatten. Resultaten från sandfiltratexperimenten visade att ett ultrafiltreringssteg efter sandfiltren skulle kunna vara en möjlig placering av ultrafiltren. Ytterligare studier krävs dock för att med säkerhet kunna bestämma den mest optimala placeringen. Sammanfattningsvis visar resultaten från experimenten lovande tecken på att en ultrafiltreringsprocess är ett möjligt alternativ för att öka Norrvattens dricksvattenreningsverks effektivitet och kapacitet.Norrvatten is the fourth largest drinking water producer in Sweden. They produce and distribute drinking water to 14 municipalities north of Stockholm. For some time, Norrvatten has studied alternative processes in order to optimise and increase the production capacity and efficiency of their drinking water treatment plant at Görvälnverket. In this project, a small-scale pilot plant has been used to study and optimise a coagulation and ultrafiltration hybrid process step in order to remove humic substances from surface water. The effect of pH, reaction time, and different feed water qualities (Görväln, Fyrisån and Görväln full scale sand filtrate) were analysed through a series of experiments performed with the pilot plant. The most optimal placement of an eventual ultrafiltration step was also studied. The results from the experiments suggested that pH in the range 6.1 to 6.7 had no large effect on the removal efficiency of fluorescent dissolved organic matter (fDOM). Instead, differences in removal efficiency could be observed between coagulant dosages which indicates that this parameter is of more importance than pH. At higher pH (> 7) removal was significantly lower. The reaction time had no effect on the removal efficiency of the plant. However, the transmembrane pressure increased ten times faster during the experiments with a shorter reaction time. These results suggested that the floc formed were smaller and thereby more tightly packed in the ultrafilter which in turn increased the pressure in the membrane. An fDOM removal of at least 50 %, though no more than 60 %, was achieved with all feed waters except for the sand filtrate which had a removal efficiency of 18 %. However, highly concentrated humic waters such as Fyrisån proved to be challenging for the plant to handle since the pressure built up rather quickly in the membrane. The sand filtrate feed water experiments indicated that an ultrafiltration step after a sand filtration process would be effective. However, further studies are required to be able to determine the most optimal placement of the ultrafiltration process. In conclusion, the results achieved with the pilot plant show promising signs of an ultrafiltration process being a viable alternative for Norrvatten to increase their drinking water treatment plant’s efficiency and capacity.
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Matson, Johan. "Coffee grounds as an adsorbent for heavy metals in water treatment : Study based on the environment around Vattenriket, Kristianstad." Thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-96299.
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One of the modern times worst environmental problem are polluted water resources. An example of source of pollution to water resources are, heavy metal leached from acid sulfate soils (ASS). When these soils are stable, which they are if they are left underwater in an anoxic environment (for example below the water table), they are often sought after since they consist of high amount of nutrients which farmers use as farmlands. ASS is therefore created when farmers drain their land and the sulfide soil gets exposed to air, resulting in its oxidation and therefore formation of sulfuric acid. In a previous study performed by scientists from Linnaeus University, it was concluded that a natural reserve located in Vattenriket, Kristianstad was possibly damaged by the drainage discharge of an adjacent acid sulfate soil. For remediation of acid sulfate soil, notably removal of metals from drainage waters, grounded coffee has been suggested to be able to perform well as an adsorbent. This study was performed to investigate how well grounded coffee could be used as an adsorbent, for calcium (Ca) and zinc (Zn), from water samples collected in Vattenriket, Kristianstad. It was also studied to see if grounded coffee could be cleaned using a sodium hydroxide solution to increase its adsorption capacity. To be able to evaluate how well it could be used as an adsorbent, it went through two different cleaning procedures and total organic carbon and pH readings was performed. The used method for this paper was to clean the grounded coffee in two different stages. The first stage consisted of using distilled water and letting it run through the residues until the water came out as transparent. Cleaning using a NaOH solution consisted of suspending the residues in a NaOH solution for 45 minutes and swapping the solution 6-8 times. After the grounded coffee had dried in an oven at 30o for 48 hours, it was put into different fraction sizes, weighed and bagged. The water samples then had to be filtered using a pump and Filtropur S 0.45 filters. Lastly, 45 falcon tubes containing 15 different amounts of grounded coffee had 50 ml of filtered water sample added to them. For analysis, atomic absorption spectroscopy was used. The results showed that the maximum amount of adsorbed calcium was achieved at 1.5g of grounded coffee in a 50 ml water solution which managed to adsorb 99.53% of calcium. The maximum amount of adsorbed zinc was achieved at 1.25g of grounded coffee in a 50 ml solution which resulted in 99.16% of adsorbed zinc. The study also showed that when the total organic carbon-content was decreasing, due to excessive cleaning, the pH was increasing. This was further proof that the grounded coffee still had residues onto its surface that could inhibit its adsorption capabilities.
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Pokhrel, Lok R., Brajesh Dubey, and Phillip R. Scheuerman. "Natural Water Chemistry (dissolved Organic Carbon, Ph, and Hardness) Modulates Colloidal Stability, Dissolution, and Antimicrobial Activity of Citrate Functionalized Silver Nanoparticles." Digital Commons @ East Tennessee State University, 2014. https://doi.org/10.1039/C3EN00017F.
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Knowledge about whether/how natural water chemistry influences the fate, dissolution, and toxicity of silver nanoparticles (AgNPs) should contribute to ecological risk assessment and informed decision making. The effects of three critical water chemistry parameters – dissolved organic carbon (DOC), pH, and hardness – were investigated on the colloidal stability, dissolution dynamics, and antimicrobial activity of citrate-functionalized AgNPs (citrate–AgNPs) against Escherichia coli. Toxicities of citrate–AgNPs and AgNO3 were also determined in the river water samples collected across three seasons (for seven months). Detectable changes in hydrodynamic diameter, surface charge, and plasmonic resonance revealed the modulating effects of the water chemistry parameters on the colloidal stability of citrate–AgNPs. Although, overall Ag release from citrate–AgNPs was low (0.33–3.62%), it increased with increasing DOC concentrations (0–20 mg L−1) but decreased with increasing pH (5–7.5) or hardness (150–280 mg L−1). Citrate–AgNP toxicity was 3–44 fold lower than of AgNO3 (Ag mass basis). Notably, higher DOC or pH conferred protection to E. coli against citrate–AgNPs or AgNO3; increasing solution hardness tended to enhance toxicity, however. Citrate–AgNPs or AgNO3 toxicity in the river water matrix revealed no seasonality. Generalized linear models developed, by parameterizing particle properties, could fairly predict empirically-derived nanotoxicity. Our results show that particle size, surface properties, ion release kinetics, and toxicity of citrate–AgNPs can be modified upon release into aquatic environments, suggesting potential implications to ecosystem health and functions.
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Lemos, Lyzandra Lais de Almeida. "O potencial hidrogeniônico (ph) como parâmetro indicador do uso abusivo do aditivo alimentar fosfato em pescado." Universidade Federal Rural do Semi-Árido, 2017. http://bdtd.ufersa.edu.br:80/tede/handle/tede/732.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Considering the abusive use of humectant agents in frozen seafood processing, and a possible relationship between the pH parameter and the phosphate food grade additive, the objective of the present study was to evaluate if there is a correlation between the pH of the tuna meat and different concentrations and time of contact of food additive phosphate. The tuna fillets (average of 225 g) were immersed in cold solutions (5°C) of sodium tripolyphosphate (STPP) and phosphates blend (concentrations) at concentrations of 3, 5 and 10% (fillet:solution ratio of 1: 1; w:v) at 30, 60 and 120 minutes. Water was used as the control group. After immersion, the samples were drained, weighed (yield calculation), frozen in ultrafreezer (-35ºC for 24 h) and stored (-35ºC) for 15 days. After this period, the samples were thawed (5°C, 24 hours), drained for 5 minutes, and weighed (yield calculation). After thawing, samples were grilled (200°C for 3 minutes on each side) and weighed (yield calculation). Samples were withdrawn after each step (immersion, thawing and cooking) and submitted to pH, phosphate (P2O5) moisture and protein analysis. The yield (gain and loss weight) was determined by the weight of the samples before and after the treatments (immersion, thawing and cooking). All food additives used in the present study (STPP and Blend) demonstrated their efficacy in water retention after immersion, thawing and cooking. There was a gradual increase in moisture content (after immersion in solutions of STPP and Blend), and a consequent increase in moisture/protein ratio suggesting a new parameter to be considered as indicative use of humectant agents in seafood. There was a gradual increase in pH and residual phosphate (P2O5) in all treatments, and still remained below the limits established by national (pH) and international (P2O5) legislation. A linear correlation was observed between pH and P2O5 values, which may become a parameter to be considered as indicative use of humectant agents (phosphates) in seafood. From the results of experiments, we suggest a critical review on the current issue, and those possible changes can be evaluated in the official parameters as indicators of abusive use of the phosphate additive in seafood and to combat economic fraud in the frozen products. It should be emphasized that these suggestions should be the focus of the collaborative study for its validation
Considerando o uso abusivo de agentes umectantes no processamento de pescado congelado, e uma possível relação entre o parâmetro pH e o aditivo fosfato, o objetivo do presente estudo foi avaliar se existe correlação entre o pH da carne do atum e diferentes concentrações e tempo de contato com o aditivo alimentar fosfato. Os filés de atum (média de 225 g) foram imersos em soluções refrigeradas (5°C) de tripolifosfato de sódio (TPF) e mistura de fosfato (blend) nas concentrações 3, 5 e 10% (proporção filé:solução de 1:1; p:v), por 30, 60 e 120 minutos. Como grupo controle utilizou-se água. Após a imersão, as amostras foram drenadas, pesadas (cálculo de rendimento), congeladas em ultrafreezer (-35ºC por 24 h) e armazenadas (-35ºC) por 15 dias. Após esse período, as amostras foram descongeladas (5°C, 24 horas), drenadas por 5 minutos, pesadas (cálculo de rendimento). Após o descongelamento, as amostras foram grelhadas (200ºC por 3 minutos em cada lado) e pesadas (cálculo do rendimento). Amostras foram retiradas após cada etapa (imersão, descongelamento e cocção) e submetidas às análises de pH, fosfato (P2O5), umidade e proteína. O rendimento (ganho/perda de peso) foi determinado pelo peso das amostras antes e após os tratamentos (imersão, descongelamento e cocção). Todos os aditivos alimentares utilizados no presente estudo (TPF e Blend) demonstraram sua eficácia na retenção de água após imersão, descongelamento e cocção. Observou-se um aumento gradual dos teores de umidade (após imersão em soluções de TPF e Blend), e consequente aumento na relação umidade/proteína que sugere um novo parâmetro a ser considerado como indicativo uso de agentes umectantes no pescado. Observou-se um aumento gradual do pH e do fosfato residual (P2O5) em todos os tratamentos, e ainda permaneceram abaixo dos limites estabelecidos pela legislação nacional (pH) e internacional (P2O5). Observou-se correlação linear entre os valores de pH e fosfato (P2O5) o qual pode se tornar um parâmetro a ser considerado como indicativo uso de agentes umectantes (fosfato) no pescado. A partir dos resultados dos experimentos, sugerimos uma revisão crítica sobre o tema, e que possíveis mudanças possam ser avaliadas nos parâmetros oficiais como indicadores de uso abusivo do aditivo fosfato em pescado e combater uma fraude econômica nos produtos congelados. Ressalta-se que essas sugestões devem ser o foco do estudo colaborativo para sua validação
2017-06-28
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Mohammed, Alahmad Suleiman. "Electrochemical and Electroflotation Processes for Milk Waste Water Treatment." Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu151309400205639.
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Gao, Yuan. "Ultrasonic Control of Ultrafiltration Membrane Fouling by Surface Water: Effects of Calcium, pH, Ionic Strength and Natural Organic Matter (NOM) Fractions." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1285123886.
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Carter, Kimberly Anne. "Impacts of Salt and pH on the Phase Behavior of Sea Spray Aerosol Proxy Films." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1534468159117872.
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Clarke, Charlotte Louise. "Investigating the host-parasite dynamics of a novel amphibian dermocystid disease in an isolated population of palmate newts in the UK." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28815.
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Emerging infectious diseases (EIDs) have been identified as a key factor in significant amphibian mortalities and global declines. Disease has been largely attributed to just two pathogens, Batrachochytrium dendrobatidis (Chytrid) and Ranavirus, however, an increasing number of amphibian disease cases across Europe are being attributed to a group of unusual fungal-like pathogens of the order Dermocystida. Despite representing an old lineage of amphibian pathogens first described in 1903, very little is known about amphibian- Dermocystids. In 2006, diseased palmate newts on the Isle of Rum, Scotland were reported. Clinical signs appeared consistent with heavy infestations of Dermocystid disease, however oedematous pathologies not previously described in the literature were also observed, suggesting a severe case of disease. This thesis develops the first comprehensive pathogen profile of a novel amphibian-infecting Dermocystid causing severe disease in an isolated population of palmate newts (Lissotriton helveticus) on the Isle of Rum, Scotland. Molecular phylogenetics and histopathology techniques were used to characterise the pathogen, confirming its affiliation to the Dermocystids and identifying it as the second formally described species in the genus Amphibiothecum (meredithae). By incorporating histopathology, field observations and study trials a broader understanding of disease dynamics was achieved. Pathogen cyst developmental stages were assigned to distinct gross pathologies, determining a putative disease cycle. In addition, a large disparity in disease outcome was evident, with cases suggesting involvement of innate immune systems with apparent host recovery, alongside cases with severe morbidity and mortality. Following the development of a pathogen profile, the spatio-temporal dynamics of disease were explored across three consecutive years, from 2014 to 2016. The temporal patterns observed within a single season were first examined across a small sub-set of sites, highlighting a degree of stability in disease prevalence and environmental variables. This within-season survey also provided a temporal dataset of disease presentation, allowing for disease progression to be assessed at the population level, investigating the impact of time on disease presentation and morbidity. For example, an overall linear trend in disease progression was observed where the burden of discrete cysts, thought to represent an initial stage of infection was highest at the beginning of the season, appearing to be ‘replaced’ by larger lesions representing later stage pathologies. Finally, ulcerations that facilitate the release of mature pathogen spores (or sporangia) occurred in the highest abundance towards the end of the season. However the prevalence of the most severe oedematous stages did not always fit with this linear progression of disease and may be driven by other factors. Understanding the within-season dynamics, and confirming a temporal stability in disease prevalence, allowed for broader spatial analysis to be performed without the need to account for samples taken at different points in time. Data collected from a broad spatial survey conducted in 2014 was explored to determine the spatial distribution of infection on Rum, and to investigate the relationships between the incidence, prevalence and severity of disease to environmental conditions and host population structure (e.g. sex ratios). Disease was widespread but heterogeneously distributed across Rum, with site-to-site variation in the incidence and prevalence linked to water pH where low pH environments were associated with low disease prevalence. An apparent sex-linked bias in disease was determined where males were more susceptible, but this does not appear to impact the host population structure of infected sites. The observed relationships between disease prevalence and environmental conditions were further utilised to test the use of disease prediction maps as a means to estimate disease across unsampled locations on the Island. Spatial surveys were subsequently conducted in 2015 and 2016, providing annual data on the distribution and prevalence of disease. Interannual variation at the site level was used to explore key factors influencing the stability of disease, identifying an association between changes in host population structure and increasing disease levels. Spatio-temporal fluctuations at the island level alluded to the overall state of disease on the island and changes to disease risk overtime. Whilst spatial clusters of changing disease prevalence were identified, which could indicate unusual patterns of epidemic spread, these conclusions would be speculative and as no consistent, significant increase in disease was determined or expansion in range, disease likely represents an endemic infection dictated heavily by etiological factors. In order to facilitate future studies and nation-wide surveys such as those conducted for Chytridiomycosis and Ranavirosis, this thesis concludes by trialling non-invasive diagnostic techniques. Environmental DNA and dermal swabbing provides the basis for the development of alternative sampling protocols to improve large-scale survey potential, and lead to a deeper understanding of these pathogens. This study represents the first formally described case of Dermocystid in the UK as well as providing the first detailed spatio-temporal study of an amphibian- Dermocystid. Identifying significant predictors of disease alongside disease prediction maps and potential methods for quick disease diagnosis, provides the tools for future, large-scale analyses to understand the distribution of disease across mainland UK, host range and the risk to native amphibian species.