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1
Rahman, Mohammad Shahedur. "Nitrification in premise plumbing systems." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/rahman/RahmanM0808.pdf.
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Monochloramine is increasingly used instead of free chlorine as a secondary disinfectant. Ammonia is introduced into water for monochloramine formation or by decay. Nitrification can have deleterious effects on water quality that may lead to regulatory violations. In this project water quality and influence of pipe material on the onset of nitrification and consequences of nitrification in premise plumbing were investigated. Also potential control strategies for nitrification were evaluated. Initially two types of copper coupons (new and old, i.e., pre-exposed to 0.1N NaOH solution) were used with water of two different carbon (2~4ppm) and ammonianitrogen (0.36~0.71ppm) concentrations. In the next experiment, pre-aged copper and PVC coupons were used with high carbon (4 ppm) and two ammonia concentrations (0.36 and 0.71 ppm). When all reactors showed complete signs of nitrification the ammonia concentration in low ammonia (0.36 ppm) feed reactors were raised to the high level (0.71 ppm). The PVC reactors were quicker in adjusting to this change. Next, the effect of copper ion, chlorite and chloramine on nitrifying simulated household plumbing systems was investigated. No significant effect of copper on nitrification was observed. Chlorite was not effective on the PVC system but inhibited the copper system at 20 ppm. Nitrification activity was also impacted significantly at a 5:1 ratio of chlorine to ammonia and ultimately stopped. To investigate the effect of nutrient conditions on metal release in a nitrifying system and the consequences of change in microbial population, influent humic and ammonia concentrations of two reactors of each set were raised to 8 ppm and 2.13 ppm respectively. Higher ammonia increased only the autotrophs while higher TOC increased only the heterotrophs. For all reactors alkalinity and pH decreased due to nitrification, with lesser effect on copper reactors. Increased TOC or nitrogen increased the copper concentration in the water. The microbial population was analyzed by PCR and DGGE. The biofilm community composition is influenced by nutrient condition and pipe material and environmental stress (chlorite or monochloramine). The presence of copper in the PVC reactor did not cause any impact on community composition.
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Lee, Juneseok. "Two Issues in Premise Plumbing: Contamination Intrusion at Service Line and Choosing Alternative Plumbing Material." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/27422.
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Worldwide water distribution infrastructure system is old and deteriorating. A water system with its myriad appurtenances (including pumps and valves and tanks) is susceptible to hydraulic transients resulting in high and low pressure waves alternatively passing through the network. While both low and high pressure events structurally tax the already weak system, there is copious evidence indicating intrusion of contaminants into the drinking water pipes from the pipeâ s exterior environment due to low pressure events associated with water hammer phenomenon. These contaminants enter into the drinking water as the home plumbing system is a passive recipient from the water main. While the major (municipal) system is readily recognized as a vast infrastructure system of nearly 1,409,800 km of piping within the United States, the minor (plumbing) system that is at least 5 to 10 times larger is generally not well analyzed. In this study, an experimental plumbing rig was designed and implemented that replicates the range of pressures encountered in actual minor water distribution systems. This research addresses how a pressure transient triggered within a house and from municipal systems can impact the service line with a possible suction effect. Experimental results on low pressure events and the accompanying numerical modeling showed good agreement. The experiment also enabled visualization of the various pressure transient phenomena. It is demonstrated that hydraulic transients triggered from water mains result in low pressures events (up to -10 psig) in service lines which can allow possible intrusion of microbial and chemical contaminants at the service line. Structural integrity of service line and hydraulic integrity at water mains should be maintained to minimize any public health risks.
In the USA, about 90% of residential drinking water plumbing systems use copper pipes. Pinhole leaks in copper plumbing pipes have become a nationwide concern because these leaks cause property damage, lower property values, and result in possibility of adversely affecting homeownersâ insurance coverage. In addition, resulting mold damage may cause health concerns. This research also addresses the concerns of the affected homeowners by enabling them to decide on whether to continue to repair or replace their plumbing system, the factors to be considered in a replacement decision, and the type of material to use for replacement. Plastic pipes such as PEX (cross-linked polyethylene), CPVC (Chlorinated Polyvinyl Chloride), and copper are considered in present analysis. Other alternatives include an epoxy coating technique on the existing piping systems, without the need to tear into walls. Multiple attributes of a plumbing system including cost (material plus labor charges), taste and odor impacts, potential for corrosion, longevity of the pipe system, fire retardance, convenience of installation or replacement, plumber or general contractorâ s opinions or expertise, and proven record in the market are considered. Attributes and material rankings are formalized within the framework of the preference elicitation tools namely AHP (Analytical Hierarchical Process). Surveys are conducted with selected homeowners in pinhole leak prone area in Southeastern US Community to observe their revealed and stated preferences. Participantsâ overall preference tradeoffs are reported in addition to comparing their revealed and stated preferences. Health effects, taste and odor of water turned out to be the most important factors from the survey. In real life, however, homeowners were not well aware of these safety issues related with plumbing materials. It is recommended that water professionals should work on bridging the gap between public perception and research results related to major and minor systems.Ph. D.
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Ohnemus, Stephen Patrick. "A locational analysis of plumbing cooperatives." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/69333.
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Bembnister, Tom. "An analysis of the effectiveness and participants' perceptions of A&K Services class titled: 2004 Plumbing code changes." Menomonie, WI : University of Wisconsin--Stout, 2005. http://www.uwstout.edu/lib/thesis/2005/2005bembnistert.pdf.
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Coogan, Laurance Andrew. "Magma plumbing beneath the Mid-Atlantic Ridge." Thesis, University of Leicester, 1998. http://hdl.handle.net/2381/30468.
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A suite of fresh,~0.75 Ma old, gabbroic samples from ODP Hole 923A on the Mid-Atlantic ridge just south of the Kane Fracture Zone, 23°N, have been studied texturally and by electron probe and ion probe. This hole penetrated ∼70 mbsf recovering 40 m of core from the basal 55 m of the hole. The core is dominated by two interlayed lithologies: poikilitic olivine gabbros and brown-pyroxene gabbros, plus volumetrically minor microgabbros, oxide gabbros and leucocratic veins. Poikilitic olivine gabbros are plagioclase +/- olivine cumulates with relatively primitive mineral composition. Horizons of poikilitic olivine gabbros in the core represent magma chamber replenishment in which the replenishing magma ponded at the base of the chamber and fractionated. Variations in plagioclase trace element compositions (e.g. La/Nd and Ba/K) in part reflect compositional variation in their parental melts derived from the mantle. Calculated equilibrium melt compositions are highly LREE depleted (Lan/Ndn as low as 0.25). Brown-pyroxene gabbros are olivine - plagioclase - clinopyroxene cumulates which have more evolved mineral compositions than poikilitic olivine gabbros. A series of major and trace element characteristics of the rocks, and textural phenomena, indicate that post-cumulus processes were important in their formation. In particular, extreme variations in incompatible element abundances, and fractionation of Zr and Y (and REE's), from the core to rim of clinopyroxene crystals occurs. It is proposed that the fractionation of the interstitial melt was caused by reaction between migration interstitial melt and the crystal assemblage (magmatic metasomatism). This led to the interstitial melt becoming highly evolved in terms of incompatible elements whilst the major elements were efficiently buffered by the crystals.
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Encarnacion, Gem Deangkinay. "Microbial ecology of nitrifying simulated premises plumbing." Diss., Montana State University, 2012. http://etd.lib.montana.edu/etd/2012/encarnacion/EncarnacionG0512.pdf.
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Because of the Stage 2 Disinfectants and Disinfection Rule limiting then concentration of disinfection by products in drinking water, the use of chloramine as an alternative to chlorine has been increasing. However, the ammonia introduced by chloramination can lead to nitrification which results in the production of nitrite and nitrate, leading to regulatory violations. Nitrification in reactors with copper and polyvinyl chloride (PVC) surfaces was established by indigenous organisms from Bozeman tap water and has been stably maintained for more than 6 years. Statistical analyses of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) profiles determined that the active bacterial populations were different in the two systems. The assemblage of the organisms was also different from the starting population (BAC influent) suggesting both material and ammonia/carbon source affect the population. No known ammonia oxidizing bacteria were detected suggesting the role of different group for ammonia oxidation. Fluorescence in situ hybridization (FISH) detected archaea in the biofilm from both reactors. Archaeal 16S rRNA gene sequences were found to be phylogenetically affiliated with known archaeal ammonia oxidizers. Two archaeal amoA sequences were amplified from the system as determined by DGGE. We propose to provisionally classify a detected archaeon as Candidatus Nitrosotenuis bozemanii, based on its affinity to Nitrosotenuis uzonensis (Hatzenpichler et al., in preparation). Bacterial abundances were comparable in the two systems but archaeal abundances were higher in the PVC reactor suggesting material effect on the overall microbial population composition and density. Enrichment in modified synthetic Crenarchaeota medium yielded a culture of archaea and bacteria that consistently oxidizes ammonia to nitrate. Attempts to isolate the archaeal component using antibiotics failed, suggesting the disruption of a possible beneficial relationship between the archaea and bacteria. Genes involved in the transformation of nitrogen within the system were also investigated and hao distantly related to that of ammonia oxidizing bacteria was detected but its potential role remains unknown. This study provides evidence of archaea associated with biofilms in drinking water and while further analysis is needed to definitively elucidate their role, results of this study prompts the reevaluation of the current concept of nitrification in drinking water. 'Co-authored by Mark D. Burr, Anne K. Camper and Mohammad Shahedur Rahman.'
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Merceret, Honor. "Our plumbing, ourselves : a public bath house." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/68754.
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Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1993.Includes bibliographical references (p. 230-231).
Cleansing for being well Cleansing for well being. This thesis will consider: --how developments in plumbing and sewage and their related fixtures, kitchens and baths, parallel cultural changes throughout history. Though these relationships are not necessarily causal, they may indicate what (critical) roles rituals in contemporary baths can take within the framework of today's socio-economic systems; -- notions of bathing for hygiene and bathing for rejuvenation. The first might be considered a 'process of elimination' while the latter a 'process of preservation'. The two are not necessarily exclusive, but there are differences between them. One involves the removal of things such as dirt, germs, and wastes while the other involves the revitalization of the spirit and body; and -- issues involving the decline of public space, security, control, and gentrification, particularly in relation to the items mentioned above. These topics are currently the highlight of many discussions and writings in architecture with today's impending conditions of homelessness, urban strife, changing domestic structure, and domestic violence. through written background and discussion as well as the design of a public bath house
by Honor Merceret.
M.Arch.
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Davis, Karen Ann 1979. "Investigation of reverse plumbing in rotary seals." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/89394.
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Szwetkowski, Kyle John. "Methylobacterium spp.: Emerging Opportunistic Premise Plumbing Pathogens." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/77659.
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Opportunistic premise plumbing pathogens (OPPPs) are responsible for many infections linked to drinking water. The annual cost of disease caused by these waterborne pathogens is $850 million. Key characteristics of these opportunistic waterborne pathogens include: disinfectant- resistant, biofilm formation, thermal-tolerance, desiccation-resistant, growth in amoebae and growth in low oxygen conditions. Methylobacterium spp. have been recognized as an emerging OPPP, so the purpose of this study was to investigate these waterborne bacteria in more detail to determine whether they have all characteristics of OPPPs. Seven Methylobacterium spp. strains were studied to measure growth in laboratory broth medium and drinking water, measure hydrophobicity on surfaces found in household plumbing, measure adherence and biofilm formation to surfaces found in household plumbing and measure susceptibility to hot water heater temperatures. Methylobacterium spp. were found to aggregate in lab broth medium and drinking water, hydrophobic on different surfaces in household plumbing, adhere readily and form biofilm on different surfaces and thermal-tolerant to water heater temperatures. These results support and identify Methylobacterium spp. as opportunistic premise plumbing pathogens.Master of Science
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Murray, John William 1972. "Simulation to assess plumbing and fire protection innovations." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/79988.
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Hernandez, Lindsey Danielle. "Magma Plumbing Systems along the Juan de Fuca Ridge." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587630136962186.
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Lee, Juneseok. "Decision Support Tool for Optimal Replacement of Plumbing Systems." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/36421.
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Pinhole corrosion leak in home plumbing has emerged as a significant issue. In the major water distribution system managed by municipalities and water utilities the costs are distributed among all subscribers. The home plumbing repair/replacement cost and possible water damage cost must be addressed by the home owner. There are also issues of the value of home, insurance rates, health consequences, and taste and odor problems. These issues have become major concerns to home owners.
Cradle to grave life cycle assessment is becoming an integral part of industrial manufacturing. In this thesis comprehensive details pertaining to life cycle assessment are presented. Copper tubing for plumbing installations is mainly obtained from recycled copper. Various stages of copper plumbing pipe manufacturing are explained. A comprehensive synthesis of various corrosion mechanisms is presented. Particular reference is given to copper plumbing pipe corrosion.
A decision support tool for replacing copper plumbing pipes is presented. The deterioration process is grouped into early, normal and late stages. Because available data reflects late stage process, an optimization, neural network and curve fitting models are developed to infer early and normal stage behavior of the plumbing system. Utilizing the inferred leak rates a non-homogeneous poisson process model is developed to generate leak arrival times. An economically sustainable replacement criterion is adopted to determine optimal replacement time.Master of Science
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McDougall, John A. "Mathematical modelling of solid transport in defective building drainage systems." Thesis, Heriot-Watt University, 1995. http://hdl.handle.net/10399/1334.
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McLean, Charlotte Elizabeth. "Shallow magmatic plumbing systems and edifices of monogenetic volcanic fields." Thesis, University of Glasgow, 2017. http://theses.gla.ac.uk/8418/.
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Magmatic plumbing systems of monogenetic volcanic fields comprise an interconnected network of sills, dykes and inclined sheets; however, the morphology, distribution and emplacement mechanisms of these shallow plumbing systems are often overlooked due to the lack of observable field data. Using seismic data provides an opportunity to understand these systems and integrate seismic-scale features with macro-scale observations from the field. Using a seismic dataset from the Faroe-Shetland Basin, NW Scotland, the Ben Nevis Monogenetic Volcanic Field (BNVF), this research provides an insight into how monogenetic volcanic fields are fed, and how the distribution of edifices can be primarily influenced by the structure of the substrate. By comparing the seismic data with field observations from three separate field studies, this research focuses in on the shallow, ductile zone (< 1 km) between the feeding intrusion(s) and the volcanic edifice, in order to determine the processes that occur during emplacement at a sub-seismic scale. This study provides a comprehensive assessment of the features of very shallow plumbing systems (< 200 m) within a variety of water-saturated settings, including: passive and dynamic peperite (blocky and fluidal); R-T structures; clastogenic dykes; gas cavities; slurry cavities; protopillows and subsurface pillows; volcaniclastic injectites; and magma lobes and fingers. The range of features displayed within the four case studies demonstrates that a variety of processes affect the emplacement of magma in the ductile zone. These processes include: (1) exploiting preferential horizons by host-rock fluidisation; (2) exploiting boundaries in the host-rock by the rotation of principal stresses; (3) explosive magmatic degassing; (4) cooling–contraction fragmentation; (5) explosions caused by rapid vapourisation of porewater; (6) a variety of molten fuel-coolant interactions (non-explosive to highly explosive); and (7) density contrasts. Monogenetic volcanic fields and their plumbing systems have been identified in reflective seismic data in exploratory offshore sedimentary basins (e.g. Southern Australia Margin and the NE Atlantic Margin). This research presents unprecedented quantitative analysis of the thermal influence of diatremes using a range of techniques (vitrinite reflectance analysis, Raman spectroscopy and fluid inclusion techniques) to produce local isothermal models of the host-rock surrounding diatremes. This aims to provide a better understanding of the overall thermal effect of monogenetic plumbing systems on reservoir porosity and permeability, and source maturity.
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Ranganathan, Aruna. "Professionalization and market closure : the case of plumbing in India." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82270.
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Thesis (S.M. in Management Research)--Massachusetts Institute of Technology, Sloan School of Management, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 29-31).
While professionalization has long been understood as a process of establishing market closure and monopoly control over work, this paper presents a case where professionalization erodes rather than establishes occupational closure. Using the case of plumbing in India, I demonstrate how the Indian Plumbing Association (IPA), a newly formed organization of internationally-trained plumbing contractors and consultants, is using the rhetoric and structures of professionalization to threaten pre-existing ethnicity-based closure enjoyed by traditional plumbers from the eastern state of Orissa. By employing a discourse of professionalism and by instituting codes, training and certification programs, professionalization in this case is hurting Orissan plumbers by changing the basis of plumbing knowledge and opening entry to outsiders. This paper concludes by suggesting that professionalization is a modern trope that does not necessarily imply monopoly benefits and higher job quality for all the members of a given occupational group.
by Aruna Ranganathan.
S.M.in Management Research
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Zhang, Jing. "A crystal window into the crustal arc magma plumbing system." Thesis, Durham University, 2016. http://etheses.dur.ac.uk/11565/.
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Open magmatic processes, including magma mingling, fractionation and assimilation, are responsible for the diversity of magma and crystal compositions common in subduction zone settings. This thesis focuses on investigating pre-eruptive open-system processes using crystal-specific studies. Particularly, we develop calcic amphibole as a robust recorder of magmatic processes. Amphibole is a common mineral phase in water-bearing arc magmas. Its stability is a complex function of temperature, pressure, oxygen fugacity, and melt and volatile compositions. We have developed a new multiple regression analysis of published trace element partitioning data between calcic amphibole and melt. We are able to retrieve statistically significant relationships for REE, Y, Sr, Pb, Ti, Zr and Nb. We also present new pressure-independent and temperature-independent empirical chemometric equations to predict melt major element chemistry from amphibole crystal compositions. This enables us to reconstruct melt chemistry from in situ analyses of amphibole in magmas and plutonic xenoliths. Linking these inverted melt compositions to the observed crystal textures allows us to make robust interpretations of magmatic processes throughout the magma plumbing system. We take the 1951 eruption products of Mt. Lamington volcano as a primary case study. Mt. Lamington is a composite volcano sitting on the Papuan Ultramafic Belt (PUB) ophiolite. The 1951 eruption produced andesitic dome lavas with numerous basaltic-andesitic enclaves and a few PUB ultramafic xenoliths. The mineralogy of the enclaves is dominated by amph+plag, similar to the andesitic lava hosts. The textures of the enclaves vary from fine-grained diktytaxitic to coarser-grained plutonic textured. We interpret this variation to result from variable cooling rates in the enclave-forming magma body when it invades the overlying andesite. The diktytaxitic enclaves contain variable proportions of host-derived amph+plag antecrysts and xenocrysts of ol+sp±cpx±amph with disequilibrium textures, indicating interaction with host lava and assimilation of foreign materials, respectively. A previous study argued that the olivine xenocrysts with chromian spinel inclusions are derived from the PUB, and thus that the PUB contaminated the Mt. Lamington magmas. We demonstrate that this is highly unlikely on the basis of morphological and compositional discrepancies between PUB ol+sp and the xenocrysts. The olivines are considered to represent crystal mush fractionated from precursor(s) of andesitic and/or pre-1951 shoshonitic lavas. Their presence in enclaves represents recycling of earlier-fractionated components through magma recharge. We also revisit and bring new insights on magmatic processes shaping the Ongatiti eruption of Mangakino volcano, amphibole-bearing plutonic nodules exposed in the lavas in Grenada, and the 1991 eruption of Mt. Pinatubo. We demonstrate that reconstructed melt compositions inferred from the rims of amphiboles in pumice clasts of the Ongatiti ignimbrite are in good agreement with the matrix glass compositions. This suggests that equilibrium between the amphibole rims and melts of matrix glass compositions is achieved. The cores of amphiboles from the Ongatiti ignimbrite show large compositional variation as well as disequilibrium textures (e.g. patchy zoning, resorption/dissolution texture), and the predicted melt compositions also display large variations. We interpret that these variations may be due to different degrees of equilibration of the amphiboles derived from crystal mushes with evolved melts over a range of timescales. This interpretation is an alternative to the model provided by an earlier study which instead suggests that source heterogeneity is a major contribution to the crystal chemical diversity in the Ongatiti ignimbrite. For amphiboles in plutonic nodules in Grenada lavas, we are able to predict the melts compositional variations from amphiboles in clinopyroxenite, hornblendite and hornblende gabbro xenoliths, in consistency with melt inclusions hosted in those cumulates. We interpret that the variations may be a result of in situ melt evolution due to extensive crystallization of the cumulate mineral phases, or equilibration of cumulate fragments with later evolved melts. Bimodal amphibole populations and hence inferred melt compositions in Mt. Pinatubo indicate magma mingling process, in consistency with conclusions of earlier studies. The inferred melt trace element compositions from bimodal groups also record co-crystallization of plagioclase, ilmenite, zircon and apatite together with amphiboles to varying extent, and the interpretation can be generally supported by petrography evidences.
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Wang, Hong. "Critical factors controlling regrowth of opportunistic pathogens in premise plumbing." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/19305.
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Opportunistic pathogens (e.g., Legionella pneumophila, Mycobacterium avium complex, Acanthamoeba polyphaga, Pseudomonas aeruginosa) residing in human-made water systems, particularly premise plumbing, are now the primary source of water-borne disease in developed countries. The prevention and control of opportunistic pathogens is a new challenge in premise plumbing due to the limited knowledge concerning the factors driving their occurrence and regrowth mechanisms, and also the complexity of premise plumbing conditions. The goal of this study is to identify key factors governing occurrence of opportunistic pathogens in drinking water distribution systems, particularly premise plumbing, via field investigations and lab-scale experiments. A molecular survey of three opportunistic pathogens (L. pneumophila, M. avium, P. aeruginosa), related groups (Legionella and mycobacteria) and two amoeba hosts (Acanthamoeba spp. and Hartmanella vermiformis) was performed in two real-word chloraminated drinking water distribution systems using quantitative polymerase chain reaction (q-PCR). A high occurrence of Legionella (" 69.0%) and mycobacteria (100%), lower occurrence of L. pneumophila (" 20%) and M. avium (" 33.3%), and rare detection of Pseudomonas aeruginosa (" 13.3%) was observed in both systems. Hartmanella vermiformis was more prevalent than Acanthamoeba. Three-minute flushing resulted in reduced gene copies of Legionella, mycobacteria, H. vermiformis and 16S rRNA genes (P<0.05) and distinct microbial community structure in postflushing water, implying strong regrowth potential of opportunistic pathogens in premise pluming.
In order to examine the influence of pipe material, disinfectant type, and water age on occurrence and persistence of the target microorganisms, triplicate simulated distribution systems (SDSs) comparing iron, cement and PVC pipe materials were fed either chlorinated or chloraminated tap water, and were sampled at water ages ranging from 1d to 5.7d. q-PCR quantification of target microorganisms in both biofilm and bulk water revealed that Legionella, mycobacteria, P. aeruginosa and both amoebas naturally colonized the six SDSs, but L. pneumophila and M. avium were not detected. Disinfectant type and dose have the strongest influence on the microbiota. Disinfectant decay was noted with water age, particularly in chloraminated SDSs (due to nitrification), generally resulting in increased microbial detection frequencies and densities with water age. Influence of pipe material became apparent at water ages corresponding to low disinfectant residual.
Natural colonization of Legionella spp., Mycobacterium spp., Acanthamoeba spp., H. vermiformis and M. avium was also observed in biofilms from five annular reactors, which were used to investigate effects of prior granular activated carbon (GAC) biofiltration and disinfectant type (chlorine, chloramine) on opportunistic pathogens under premise plumbing conditions. GAC pre-treatment effectively reduced total organic carbon (TOC). In most cases, total bacteria and opportunistic pathogens were higher in undisinfected annular reactors, but the levels were not proportional to the level of GAC pre-treatment/TOC. Chlorine was more effective for controlling mycobacteria and Acanthamoeba, whereas chloramine was more effective for controlling Legionella. Both chlorine and chloramine effectively reduced M. avium and H. vermiformis numbers. Pyrosequencing of 16S rRNA genes in biofilms revealed a significant effect of GAC pre-treatment and disinfectant type on the microbial community structure.
Overall, the study provides insights to critical factors triggering proliferation of opportunistic pathogens in drinking water systems. Knowledge gained from this study can assist in formulating practical guidance for drinking water utilities and water consumers in terms of opportunistic pathogen prevention and control. "
Ph. D.
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Scott, Jameson Lee. "Petrological Constraints on Magma Plumbing Systems along Mid-Ocean Ridges." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322599745.
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Kindred, Thomas. "Checkerboard plumbings." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6160.
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Knots and links $L\subset S^3$ carry a wealth of data. Spanning surfaces $F$ (1- or 2-sided), $\partial F=L$, especially {\bf checkerboard} surfaces from link diagrams $D\subset S^2$, help to mine this data. This text explores the structure of these surfaces, with a focus on a gluing operation called {\bf plumbing}, or {\it Murasugi sum}.
First, naive classification questions provide natural and accessible motivation for the geometric and algebraic notions of essentiality (incompressibility with $\partial$-incompressibility and $\pi_1$-injectivity, respectively). This opening narrative also scaffolds a system of hyperlinks to the usual background information, which lies out of the way in appendices and glossaries.
We then extend both notions of essentiality to define geometric and algebraic {\it degrees} of essentiality, $\underset{\hookrightarrow}{\text{ess}}(F)$ and $\text{ess}(F)$. For the latter, cutting $S^3$ along $F$ and letting $\mathcal{X}$ denote the set of compressing disks for $\partial (S^3\backslash\backslash F)$ in $S^3\backslash\backslash F$, $\text{ess}(F):=\min_{X\in\mathcal{X}}|\partial X\cap L|$. Extending results of Gabai and Ozawa, we prove that plumbing respects degrees of algebraic essentiality, $\text{ess}(F_1*F_2)\geq\min_{i=1,2}\text{ess}(F_i)$, provided $F_1,F_2$ are essential. We also show by example that plumbing does not respect the condition of geometric essentiality.
We ask which surfaces de-plumb uniquely. We show that, in general, essentiality is necessary but insufficient, and we give various sufficient conditions.
We consider Ozawa's notion of representativity $r(F,L)$, which is defined similarly to $\text{ess}(F)$, except that $F$ is a closed surface in $S^3$ that contains $L$, rather than a surface whose boundary equals $L$. We use Menasco's crossing bubbles to describe a sort of thin position for such a closed surface, relative to a given link diagram, and we prove in the case of alternating links that $r(F,L)\leq2$. (The contents of Chapter 4, under the title Alternating links have representativity 2, are first published in Algebraic \& Geometric Topology in 2018, published by Mathematical Sciences Publishers.) We then adapt these arguments to the context of spanning surfaces, obtaining a simpler proof of a useful crossing band lemma, as well as a foundation for future attempts to better classify the spanning surfaces for a given alternating link.
We adapt the operation of plumbing to the context of Khovanov homology. We prove that every homogeneously adequate Kauffman state has enhancements $X^\pm$ in distinct $j$-gradings whose traces (which we define) represent nonzero Khovanov homology classes over $\mathbb{Z}/2\mathbb{Z}$, and that this is also true over $\mathbb{Z}$ when all $A$-blocks' state surfaces are two-sided. A direct proof constructs $X^\pm$ explicitly. An alternate proof, reflecting the theorem's geometric motivation, applies our adapted plumbing operation. Finally, we describe an interpretation of Khovanov homology in terms of decorated cell decompositions of abstract, nonorientable surfaces, featuring properly embedded (1+1)-dimensional nonorientable cobordisms in (2+1)-dimensional nonorientable cobordisms. This formulation contains a planarity condition; removing this condition leads to Khovanov homology for virtual link diagrams.
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Le, Rene. "Drain line clogs with a 1.6 gallon per flush water closet." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/19223.
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Master of ScienceDepartment of Architectural Engineering and Construction Science
Thomas Logan
Typical building sanitary lines are sloped at a minimum of 1/8” to utilize gravity and prevent liquid separation from solid waste. The purpose of this research is to analyze how a lesser amount of water from a 1.6 gallon per flush water closet affects drainage in a four inch diameter pipe at 1/4" slope. Low flow water closet manufacturers ensure that waste clears the bowl, but there is no significant research following the flushed water further down the pipe line. This research utilizes a 1.6 gallon per flush floor-mounted water closet connected to 30 feet of sloped four inch PVC Drain Waste Vent piping. Data presented from 25 flush trials indicates that further research needs to be conducted at a smaller pipe diameter. Four-inch piping is too large, causing the 1.6 gallons of water to quickly lose the required force over the course of 30 feet, resulting in pipe line clogs. An average of four additional water-only flushes are necessary to completely clear the test media and toilet paper from the pipe. This research references previously published research and focuses on test results presented by the Plumbing Efficiency Research Coalition. Two case studies of city wide replacements of old water closets are presented to discuss the viability of city wide mandates in relation to water conservation.
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Mullis, Summer. "Adherence and Biofilm Formation of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium abscessus in household plumbing." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/44778.
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Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and found in drinking water distribution systems and household plumbing. They are opportunistic pathogens of humans, causing lung disease. Their ability to adhere and form biofilm is attributed to a waxy, lipid-rich, cell envelope. This highly hydrophobic envelope also contributes to the characteristic antibiotic-, chlorine-, and disinfectant- resistance of NTM.
NTM in household plumbing reside primarily in biofilms and the ability to form biofilm has been linked to virulence. Shedding of cells from biofilm and the subsequent aerosolization of microorganisms through showerheads presents a significant public health risk, particularly to those individuals with associated risk factors.
Three species of NTM, Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium abscessus, were examined for adherence and biofilm formation on surfaces common to household plumbing systems, including glass, copper, stainless steel, polyvinyl chloride, and galvanized steel. All experiments were conducted with sterile, Blacksburg tap water in a CDC Biofilm Reactor.
Highest adherence was observed by M. avium on galvanized steel surfaces, reaching 15,100 CFU/cm2 surface at 6 hours incubation at room temperature. After 3 weeks incubation at room temperature, biofilm formation of M. avium was also highest on galvanized steel surfaces, reaching 14,000,000 CFU/cm2 surface. Lowest adherence was observed by M. abscessus on polyvinyl chloride (PVC) surfaces, reaching 40 CFU/cm2. Lowest biofilm formation was observed by M. intracellulare on glass surfaces, reaching 5,900 CFU/cm2.
Surfaces, such as galvanized (zinc), on which high adherence and biofilm formation was observed, should be avoided in household plumbing systems of NTM patients and individuals at risk for developing NTM disease. Additionally, surfaces such as copper, harbor fewer NTM and may provide a safer alternative for household plumbing of NTM patients.Master of Science
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Le, Anh. "Stratigraphic evolution and plumbing system of the Cameroon margin, West Africa." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/stratigraphic-evolution-and-plumbing-system-of-the-cameroon-margin-west-africa(94a13f64-a927-47b6-b456-a0b57c0e5494).html.
Full textAbstract:
The Kribi-Campo sub-basin is the northernmost of a series of Aptian basins along the coast of West Africa. These extensional basins developed as a result of the northward progressive rifting of South America from West Africa, initiated c. 130 Ma ago. Post-rift sediments of the Kribi-Campo sub -basin contain several regional unconformities and changes in basin-fill architecture that record regional tectonic events. The tectono-stratigraphic evolution and plumbing system has been investigated using a high-quality 3D seismic reflection dataset acquired to image the deep-water Cretaceous-to-Present-day post-rift sediments. The study area is located c. 40 km offshore Cameroon in 600 to 2000 m present-day water depth, with full 3D seismic coverage of 1500 km2, extending down to 6.5 seconds Two-Way Travel time. In the late Cretaceous the basin developed as a result of tectonism related to movement of the Kribi Fracture Zone (KFZ), which reactivated in the late Albian and early Senonian. This led to inversion of the early syn-rift section overlying the KFZ to the southeast. Two main fault-sets - N30 and N120 - developed in the center and south of the basin. These normal faults propagated from the syn-rift sequences: the N120 faults die out in the early post-rift sequence (Albian time) whilst N30 faults tend to be associated with the development of a number of fault-related folds in the late Cretaceous post-rift sequence, and have a significant control on later deposition. The basin is filled by Upper Cretaceous to Recent sediments that onlap the margin. Seismic facies analysis and correlation to analogue sections suggest the fill is predominantly fine-grained sediments. The interval also contains discrete large scale channels and fans whose location and geometry were controlled by the KFZ and fault-related folds. These are interpreted to contain coarser clastics. Subsequently, during the Cenozoic, the basin experienced several tectonic events caused by reactivation of the KFZ. During the Cenozoic, deposition was characterized by Mass Transport Complexes (MTCs), polygonal faulting, channels, fans and fan-lobes, and aggradational gullies. The main sediment feeder systems were, at various times, from the east, southeast and northeast. The plumbing system shows the effects of an interplay of stratigraphic and structural elements that control fluid flow in the subsurface. Evidence for effective fluid migration includes the occurrence of widespread gas-hydrate-related Bottom Simulating Reflections (BSRs) 104 - 250 m below the seabed (covering an area of c. 350 km2, in water depths of 940 m - 1750 m), pipes and pockmarks. Focused fluid flow pathways have been mapped and observed to root from two fan-lobe systems in the Mid-Miocene and Pliocene stratigraphic intervals. They terminate near, or on, the modern seafloor. It is interpreted that overpressure occurred following hydrocarbon generation, either sourced from biogenic degradation of shallow organic rich mudstone, or from effective migration from a thermally mature source rock at depth. This latter supports the possibility also of hydrocarbon charged reservoirs at depth. Theoretical thermal and pressure conditions for gas hydrate stability provide an opportunity to estimate the shallow geothermal gradient. Variations in the BSR indicate an active plumbing system and local thermal gradient anomalies are detected within gullies and along vertically stacked channels or pipes. The shallow subsurface thermal gradient is calculated to be 0.052 oC m-1. With future drilling planned in the basin, this study also documents potential drilling hazards in the form of shallow gas and possible remobilised sands linked with interconnected and steeply dipping sand bodies.
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Mazzini, Adriano Luigi. "Methane-related authigenic carbonates : implications for seeps and hydrocarbon plumbing systems." Thesis, University of Aberdeen, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424975.
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Geophysical surveys allowed characterization of gas-charged sediments and targeting of seepage sites. Acoustic and seismic records revealed that at these locations the release of the hydrocarbon-rich fluids mainly occur from reservoirs sited below the seepage sites or from the dissolution of gas hydrates. Both the size of the minerals and the shape of the authigenic carbonate deposits appear to be related to the seepage conditions and the lithology of the enclosing host sediment. The slabs retrieved on the seafloor or on the subsurface from mud volcano structures consisted of micrite-cemented mud breccia and hemipelagic sedimentary units present. At these sites, finer grained sediments (or gas hydrates) appear to buffer the fluid seepage thereby enhancing the precipitation of authigenic carbonate in the more porous layers, forming slab shaped deposits. Most of the irregularly shaped deposits form the studied pockmarks showed micritic/sparitic calcite- and occasionally aragonite-cemented hemipelagic sediments with associated chemosynthetic fauna. These chemoherms arise when fluids seep through the sediment allowing a diffuse colonization of chemosynthetic fauna on the seafloor that becomes gradually cemented. The formation of tubular features in the subsurface seems to occur when methane-saturated impermeable sediments include weakness zones where the seepage of hydrocarbon-rich fluids is concentrated. Irregularly shaped deposits consisting of sparitic, zoned carbonate, devoid of hemipelagic sediments, are typical of settings where fluids seep through open fractures in more consolidated sediments. There is an association of seepage carbonate deposits, and injected sandstones above hydrocarbon reservoirs. The modelling of this plumbing system suggests that similar pathways can be used for the seepage of hydrocarbon-rich fluids and sand injections.
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Batterton, Shawn Henry. "Water Hammer: An Analysis of Plumbing Systems, Intrusion, and Pump Operation." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/35606.
Full textAbstract:
This thesis provides a comprehensive look at water hammer with an emphasis on home plumbing systems. The mathematics of water hammer are explained, including the momentum and continuity equations for conduits, system construction, and the four-point implicit finite difference scheme to numerically solve the problem. This paper also shows how the unsteady momentum and continuity equations can be used to solve water distribution problems instead of the steady-state energy and continuity equations, along with the examples problems which show that an unsteady approach is more suitable than the standard Hardy-Cross method. Residential plumbing systems are examined in this paper, household fixtures are modeled for their hydraulic functions, and several water hammer simulations are run using the Water Hammer and Mass Oscillation program (WHAMO). It is determined from these simulations that the amount of air volume in the system is a key factor in controlling water hammer. Abnormal pump operation is clearly explained including a description of the four quadrants and eight zones of operation as well as the mathematics and a numerical scheme for computation. Low pressures caused by transients can lead to intrusion and contamination of the drinking water supply. Several scenarios are simulated using the WHAMO program and cases are provided in which intrusion occurs. From the intrusion scenarios, key factors for intrusion to occur during transients include the starting energy in the system, the magnitude of the transient, the hydraulics of the intrusion opening, and the external energy on the pipe (the level of the groundwater table). A primer for using WHAMO is provided as an appendix as well.Master of Science
25
Heim, Timothy Howard. "Impact of Polymeric Plumbing Materials on Drinking Water Quality and Aesthetics." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/32260.
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The use of polymer pipes is now very common in home plumbing and other parts of the drinking water distribution system. Many taste and odor complaints in drinking water are known to originate from contact of water with materials. The ability of polymer pipes used in home plumbing to affect drinking water quality and aesthetics was investigated using the Utility Quick Test (UQT). Analysis of water quality and aesthetics were conducted in the absence of disinfectant and the presence of either chlorine or chloramines. A Flavor Profile Analysis (FPA) panel was trained according to Standard Methods 2170B to evaluate the organoleptic characteristics of the samples. Laboratory analyses were performed to determine levels of total organic carbon (TOC), disinfectant residual, pH and to attempt to identify specific volatile organics.
The first part of this study investigated HDPE, cPVC and epoxy lined copper pipes using the UQT method. Both HDPE and epoxy-lined copper had significant effects on water quality and aesthetics during the approximately 10 day exposure of the UQT. HDPE and epoxy-lined copper leached significant amounts of TOC and consumed more disinfectant than controls, but in different amounts. cPVC was the most inert of the materials tested and had the least impact on water quality and did not contribute any significant odor. None of the pipes tested appeared to contribute trihalomethanes to drinking water, but further analysis revealed that the compounds may actually be generated and subsequently sorbed into pipe walls. These data show the effects of newly installed polymeric pipe materials and their potential to impact water quality in differing capacities.
The second part of this study compared the results of the UQT on HDPE, epoxy lined copper, cPVC, PEX-a and PEX-b with the goal of comparing and contrasting how five different polymeric plumbing materials can impact drinking water quality. Results demonstrated the short-term ability of all pipe materials except cPVC to impact water quality and aesthetics. This data could potentially be useful in generating selection criteria for homeowners and plumbing professionals regarding the impact of newly installed plumbing materials.
Master of Science
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Ladd, Jonathan Stuart. "An Evaluation and Pressure-Driven Design of Potable Water Plumbing Systems." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/32912.
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Potable water distribution systems are broken into major and minor distribution networks. Major water distribution networks refer to large-scale municipal pipe systems extending from the treatment plant to the upstream node of the water service line for buildings. Minor water distribution systems, also referred to as plumbing water distribution systems, run from the upstream node of the water service line to all interior plumbing fixtures and demand nodes associated with the building. Most texts and research papers focus on major systems, while only a small number of documents are available concerning the design and analysis of minor systems. In general, the available minor system documents are quite prescriptive in nature. This thesis presents a comprehensive evaluation of contemporary plumbing water distribution system design. All underlying theory is explained and advantages and drawbacks are discussed. Furthermore, contemporary methods for designing minor distribution systems have come under recent scrutiny. Issues have been raised regarding the accuracy of water demand estimation procedures for plumbing systems, namely, Hunter's method. Demand estimates are crucial for designing minor piping systems. The formulation and application of a pressure-driven design approach to replace Hunter-based design methods is presented. EPANET, a commonly used hydraulic modeling software package, is utilized to evaluate network behavior. Example applications are presented to illustrate the robustness of a pressure-driven approach, while also allowing the evaluation of plumbing water distribution system performance under worst-case loading conditions.Master of Science
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Dahrén, Börje. "Magma plumbing architecture in Indonesia and the North Atlantic Igneous Province." Doctoral thesis, Uppsala universitet, Mineralogi, petrologi och tektonik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-267764.
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Magma plumbing systems represent the physical framework of magma transport and storage from the source region in the mantle, through the crust, until reaching the surface in a volcanic eruption. Characterising the different aspects of magma plumbing, in particular the distribution of magma storage zones throughout the crust, is of key importance to better understand the behaviour of individual volcanoes. In particular, shallow crustal magma storage and associated magma-crust interaction processes could potentially explain some of the worlds most unpredictable and explosive volcanoes. This thesis studies magma plumbing architecture in the Sunda Arc (Indonesia), and the North Atlantic Igneous Province, based on elemental and isotope geochemistry, and derived petrological modelling. In this study, I have employed petrological models, so called geothermobarometers, to calculate pressures and temperatures (P-T) of crustal magma storage. Geothermobarometers are calibrated thermodynamic formulations based on the composition of magmatic minerals and their co-existing melt as a function of the P-T conditions of crystallisation. Using the calculated P-T estimates, I was able to derive the depth of magma storage, and thereby reconstruct the architecture of magma storage systems. A number of different geothermobarometers based on different mineral phases, including plagioclase, clinopyroxene and olivine, were used for this purpose, The geothermobarometric modelling was combined with additional elemental and isotope geochemical analyses, as well as collaborations with geophysical investigations. These additional approaches were used to corroborate the findings of the geothermobarometric modelling, and also to model and quantify magma-crust interaction processes that take place during crustal magma storage, such as assimilation of crustal lithologies into the magmatic system. The findings of this thesis build upon the growing body of evidence in support of the prevalence of shallow magma storage in different volcanic settings worldwide. This realisation is relevant to volcano monitoring and hazard mitigation worldwide.
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Díez, Mikel. "Studies of the mechanics and structure of shallow magmatic plumbing systems." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002436.
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Díez, Mikel. "Studies of the Mechanics and Structure of Shallow Magmatic Plumbing Systems." Scholar Commons, 2008. https://scholarcommons.usf.edu/etd/214.
Full textAbstract:
Volcanic activity, and the resultant deposits and structures at the Earth's surface, are the outcome of the inner workings of underground magmatic plumbing systems. These systems, essentially, consist of magma reservoirs which supply magma to the surface through volcanic conduits feeding volcanic eruptions. The mechanics and structure of plumbing systems remain largely unknown due to the obvious challenges involved in inferring volcanic processes occurring underground from observations at the surface. Nevertheless, volcanologists are beginning to gain a deeper understanding of the workings and architecture of magmatic plumbing systems from geophysical observations on active volcanoes, as well as from geological studies of the erosional remnants of ancient volcanic systems.
In this work, I explore the relationship between the structure and mechanics of shallow plumbing systems and the volcanic eruptions these systems produce. I attempt to contribute to the understanding of this complex relationship by linking geological and geophysical observations of an eroded basaltic subvolcanic system, and the eruptive and tectonic activity of an active volcano, with mathematical models of magma ascent and stress transfer.
The remarkable exposures of the Carmel outcrop intrusions, near the San Rafael swell, southeast Utah, U. S. A., allow detailed geological and geophysical observations of the roots of volcanic conduits that emerge from a subhorizontal magma feeder reservoir. These observations reveal a new mechanism for magma ascent and eruption triggering through gravitational instabilities created from an underlying feeding sill, and shed light on the mechanics of sill emplacement. Geophysical and geological observations of the 1999 and xii 1992 eruptions of the Cerro Negro volcano, Nicaragua, are used to explore the coupling between changes in the stress field and the triggering of volcanic eruptions, and magma ascent through the shallow crust. Modeling results of stress transfer and conduit flow highlight the importance of the surrounding stress field and geometry of the volcanic conduits that comprise shallow plumbing systems.
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Hottel, Wesley Johnathan. "Whole genome sequencing analysis of Legionella in hospital premise plumbing systems." Diss., University of Iowa, 2019. https://ir.uiowa.edu/etd/6767.
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Legionella bacteria, the causative agent of Legionaries’ disease and Pontiac fever, are ubiquitous in fresh-water environments including man-made water systems. Incidence of legionellosis is increasing in the United States resulting in thousands of cases every year. Infection via aerosols generated by showers, faucets, cooling towers, spas, fountains, and other water fixtures has been identified as the primary source of transmission. Legionella bacteria pose a significant public health threat, particularly in health care and long term care settings as Legionella can readily colonize the plumbing systems and infect the vulnerable patient population. One species, Legionella pneumophila (Lp), is responsible for over 90% of the known cases of Legionnaires’ disease. The importance of genetic diversity of Lp and non-pneumophila strains in human disease remains an area of ongoing research.
Little is known in regard to the phylogenetic diversity of environmental strains, particularly strains that colonize facilities with high risk populations such as hospitals. Whole-genome sequencing (WGS) analysis, is an emerging tool used to support epidemiological investigation of cases of legionellosis and can be used to describe and establish phylogenetic relationships between environmental strains and clinical cases. The advantage of this method is the ability to differentiate bacteria down to the level of single nucleotide polymorphisms (SNPs). However, it was unknown whether current WGS methods accurately represent the potential SNP diversity among Lp isolates from the same environmental sample.
It is unclear as to why certain strains tend be associated with clinical cases more than others, but certain genes referred to as virulence factors may be related to the relative pathogenicity of Legionella strains. Further investigation into virulence factors and antibiotic resistance factors could be used in future risk assessment of environmental Legionella. Additionally, Legionella have the potential for high genetic diversity due to recombination events, and gene transfer can occur between distinct Legionella species and strains. There is a lack of research on the potential sharing of virulence factor genes between Legionella strains typically associated with disease and those considered to be non-virulent.
The goal of the work presented in this thesis is to describe the diversity of phylogenetic relationships between Lp isolates found in hospital premise plumbing systems, to estimate the genetic diversity among Lp found in the same environmental sample, and to identify virulence and antibiotic resistance genes shared between Legionella strains. A better understanding of the genetic diversity of environmental Lp could inform future surveillance and outbreak investigations by demonstrating the need to collect samples from multiple sites within a facility, and identifying shared virulence and antibiotic resistance genes between Legionella species and strains could apprise future risk assessment.
WGS was utilized to describe the phylogenetic relationships of 81 Lp isolates from five hospitals. Individual hospitals were found to have distinct strains of Lp. For some strains, highly conserved subpopulations were collected from the same room over time, whereas other strains did not cluster by room. Using prospectively collected isolates from two hospitals, the mean number of SNP differences among isolates from the same environmental sample was found to differ between hospitals (0.4 versus 7.5).
The presence of virulence factors and antibiotic resistance genes in Legionella species and strains was described. An analysis of 10 virulence factor genes revealed that Lp likely did not share these genes with Legionella anisa, a species generally considered to be non-virulent. Within Lp strains there was no clear difference between the Lp strains considered to be more virulent and those considered to be less virulent. A few antibiotic resistance genes were also identified. Following an in vitro assay, only the identified genes associated with macrolide resistance, LpeA and LpeB, were found to impact a quantifiable measure of antimicrobial resistance.
The results of these studies emphasize the importance of understanding the context of an individual facility in Legionella related studies. Importantly, the observations or trends of one facility should not necessarily be applied to another. Legionella genetic diversity was highly conserved in some facilities, whereas in others there was greater diversity as measured by SNP differences. Within sample SNP differences was also variable between hospitals. The virulence findings gave a clear indication of the limited virulence capacity of L. anisa. These findings could explain the limited potential of L. anisa to cause disease in humans. However, a lack of difference among Lp strains may be cause to reassess the potential risk of these other strains especially in diagnostic practices. Finally, some strains of Lp have genes that may contribute to resistance to the leading antibiotic treatments for Legionnaires’ disease. Overall, this research further demonstrates the power of WGS as multiple questions can be addressed using this methodology.
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Douglas, Christopher J. "Instantaneous Water Demand Estimates for Buildings with Efficient Fixtures." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1561996040464642.
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Proctor, Caitlin Rose. "Effect of Various Water Chemistry Factors on Legionella Proliferation and the Premise Plumbing Microbiome Composition." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/56622.
Full textAbstract:
Premise plumbing, the pipes and fixtures at the building level, present a unique challenge for maintaining drinking water quality. Of particular concern are opportunistic pathogens, including Legionella pneumophila which can regrow in premise plumbing and cause disease in immunocompromised populations. The goal of this work was to explore engineering methods for control of L. pneumophila and total regrowth. The first line of study involved a series of experiments with simulated glass water heaters (SGWHs) to investigate interactions between specific water chemistry factors and L. pneumophila regrowth, and the second used laboratory grade purified water to investigate the limits of a nutrient control approach for biological stability.
Several water chemistry factors including assimilable organic carbon (AOC) content, granular activated carbon (GAC) biofiltration, plumbing materials, copper concentrations and temperature were investigated using SGWHs. AOC is the carbon available for bacteria growth in drinking water. Results indicated that AOC reduction may be a promising method for controlling L. pneumophila and total bacteria regrowth, but there may be a point at which AOC reduction is no longer effective. Prior GAC biofiltration removed organic carbon and was effective in controlling total bacterial regrowth in SGWHs, but actually encouraged L. pneumophila regrowth.
A wide variety of materials typically encountered in premise plumbing was investigated and only had limited effect on proliferation of L. pneumophila and total bacteria. The effects were dynamic, even with long-term studies. Copper pipes held promise for control of L. pneumophila, as did copper concentration across a range of pHs. Aqueous copper concentration released from pipes was dependent on temperature, however, and thus this control method may not be applicable in all hot water lines.
The peak temperatures for L. pneumophila proliferation fell between 41 and 45 °C, temperatures which could be encountered in a hot water distribution system when the water heater is set to 48 °C, as is often recommended with scalding and energy concerns. A constant temperature of 53 °C seemed to provide control of L. pneumophila, but recolonization is possible even at these high temperatures.
Work with laboratory grade water indicated that extreme control of nutrients was not enough to completely control regrowth in premise plumbing. With stagnation in the cleanest conditions, a 2-log increase of a diverse group of bacteria was observed within 10 days. As drinking water can never achieve such nutrient removal, this study presents the limits of nutrient removal as a strategy for regrowth control.
This work explored both the potential and the limitations of several mechanisms for controlling regrowth in premise plumbing. Understanding how these water chemistry factors affect L. pneumophila and total bacterial regrowth is critical to identifying the most effective engineering controls.Master of Science
33
Kochanowski, Kathryn. "Bathrooms can be easier to use! /." Online version of thesis, 1990. http://hdl.handle.net/1850/10965.
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Wilkes, Michael. "Basin plumbing dynamics : modelling fluid flow in the Weald Basin, Southern England." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357275.
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Tan, Jessica Sinyin 1977. "Noise performance of erbium-doped fiber amplifiers with forward and reverse plumbing." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86506.
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Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 59-62).
by Jessica Sinyin Tan.
S.B.and M.Eng.
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Methvin, Rachel M. "Microbial Ecology of Acanthamoeba polyphaga and Sulfate-Reducing Bacteria in Premise Plumbing." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/32713.
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Great advances have been made in the last 100 years in the effort to provide safe and reliable potable water. Unfortunately, organisms surviving the water treatment process still cause illnesses in the population. Acanthamoebae are ubiquitous in the environment and are resistant to commonly used disinfection methods. In addition to being pathogenic on their own, Acanthamoeba spp. are capable of acting as a host to pathogenic bacteria in potable water. The amoebae provide the bacteria with protection from chemical and physical means of disinfection. In this way many pathogens that would otherwise be killed in the water treatment process survive and are capable of infecting water customers.
Most likely due to experimental limitations discussed herein, the concentration of organic carbon in solution was not found to affect the number of Acanthamoeba polyphaga surviving within reactors designed to model residential water tanks. A copper ion concentration of 1.3 mg/L was determined to be an effective disinfectant against A. polyphaga trophozoites, while free chlorine at 10 mg/L and monochloramine at 50 mg/L were deemed effective against trophozoites.
Sulfate-reducing bacteria (SRB) are suspected to be causative agents in copper pitting corrosion. SRB have been found in tubercles covering pits in many homes experiencing pinhole leaks, but the mechanisms of the survival of these organisms in potable water systems are poorly understood. Nutrient studies conducted show that the absence of nitrogen in solution may encourage copper corrosion by SRB. In addition, a medium specifically designed to encourage SRB growth resulted in a large increase in copper corrosion as compared to the control water.Master of Science
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StClair, Justin Monroe. "Practical Impacts of Galvanic Corrosion in Water Service Lines and Premise Plumbing." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/49583.
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There is emerging concern about the potential for elevated lead in water after water utilities conduct EPA mandated (or voluntary) partial replacements of existing lead service lines. Connections between dissimilar metals results in the accelerated corrosion of the less noble metal via galvanic attack, increasing metal concentrations in water and posing potential public health risks. Many practical problems associated with stopping galvanic attack between copper:galvanized iron and copper:lead via use of dielectrics have also been raised.Galvanic corrosion can be effectively stopped by isolating the dissimilar metals; however, completely eliminating electrical continuity may not always be practical or allowed by code. Instead, increasing separation distance between the two metals was hypothesized to considerably reduce galvanic corrosion. Galvanic corrosion and lead leaching were evaluated for lead:copper connections with varying separation distances while maintaining electrical continuity. Increased distance between lead and copper pipe dramatically reduced the galvanic current and the magnitude of lead release. Galvanized iron and copper connections were also investigated using various commercial fittings, and results verified that a controlling factor was separation distance between the two dissimilar metals.
When considering the long-term behavior of partially replaced lead service lines, detrimental effects from galvanic corrosion worsened with time. Even when water was sampled consistently at moderate flow rate, the condition representing traditional partial service line replacement was 40% worse than a full lead service line. At elevated flowrates, lead concentrations and variability increased for partly replaced lead pipe versus full lead pipe due to reservoirs of lead rust formed via galvanic corrosion. At low flowrates, these negative impacts were not observed. Finally, crevices formed by the use of commercial couplings increased lead release.
Overall, the results enhance practical understanding of galvanic corrosion impacts and use of dielectrics in water service lines and premise plumbing.
Master of Science
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Williams, Krista Ann. "Relationship Between Organic Carbon and Opportunistic Pathogens in Simulated Premise Plumbing Systems." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/78151.
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Consumer exposure to opportunistic pathogens in potable water systems poses a significant challenge to public health as manifested by numerous cases of pneumonia, non-tuberculosis lung disease, and keratitis eye infections. Water utilities have extensive understanding in control of heterotrophic and coliform bacteria re-growth in water distribution systems via disinfection, control of assimilable organic carbon (AOC), and biologically degradable organic carbon (BDOC). However, much little is known about the effect of AOC on the proliferation of heterotrophic bacteria and pathogens within premise plumbing. This thesis is the first systematic examination of opportunistic pathogen persistence and amplification in simulated glass water heaters (SGWH) as a function of influent organic matter concentration. The role of plumbing conditions that may internally generate AOC is critically examined as part of this evaluation.
Strong correlations were often observed between influent organic matter and heterotrophic bacteria in effluent of SGWH as indicated by 16S rRNA gene abundance (average R2 value of 0.889 and 0.971 for heterotrophic organisms and 16S rRNA respectively). The correlation was strongest if water turnover was more frequent (every 48-72 hours) and decreased markedly when water changes were less frequent (stagnation up to 7 days). No simple correlations were identified between the concentration of pathogenic bacteria (L. pneumophila, M. avium, A. polyphaga, and H. vermiformis) and AOC, although correlations were observed between M. avium and TOC over a limited range (and only for a subset of experiments). Indeed, there was little evidence that Legionella and Acanthamoeba proliferated under any of the conditions tested in this work.
Parallel experiments were conducted to examine the extent to which factors present in premise plumbing (e.g. sacrificial magnesium anode rods, cross-linked polyethylene, nitrifying bacteria, and iron) could influence water chemistry and influence growth of bacteria or specified pathogens. Although these factors could strongly influence pH, dissolved oxygen concentrations, and levels of organic matter (e.g. iron, magnesium, nitrifying), there was no major impact on effluent concentrations of either heterotrophic bacteria or premise plumbing pathogens under the conditions investigated.
While additional research is needed to confirm these findings, at present, there is no evidence of correlations between organic matter and pathogen concentrations from SGWH under conditions tested. Substantial effort was also invested in attempting to identify SGWH and oligotrophic nutrient conditions that would consistently support L. pneumophila and A. polyphaga amplification. A review of the literature indicates no prior examples of large scale amplification of these microorganisms at nutrient levels commonly found in synthesized potable water. It is likely that a complex combination of abiotic and biotic factors (i.e. micronutrients, necrotrophic growth, ambient water temperature, disinfectant type and dose, plumbing materials, water usage patterns), which are not yet fully understood, control the amplification and viability of these pathogenic organisms in premise plumbing systems.Master of Science
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Singh, Inderjit. "Significance of building and plumbing specifics on trace metal concentrations in drinking water." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/28724.
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Samples were taken from 72 high-rise apartment suites (6 suites in 12 individual high-rise towers) and 60 single-family houses located within the Greater Vancouver Regional District. The influence of the following factors on trace metal concentrations in 1-L first-flush drinking water samples and running hot water samples was investigated: building height, location, plumbing age, type of plumbing and type of building. Results of this survey show that with the exception of building height, all factors had a correlation with one or more of the trace metals investigated. The trace metals examined were lead, copper, iron and zinc. Lead was influenced primarily by building type, copper by plumbing age and type of plumbing and iron by location. Elevated lead levels were associated with high-rise samples. New copper plumbing systems resulted in high copper levels. Highest iron levels in the drinking water were measured in the East location. Zinc did not show a distinct correlation with any of the factors investigated.
Brass faucets were the primary source of zinc in tap water. They also contributed substantially to the lead detected in the 1-L first-flush sample. Metal concentrations measured in high-rise and house samples were compared with U.S. Environmental Protection Agency's (USEPA) maximum contaminant levels (MCLs) and the proposed no-action level for lead1. In high-rise samples, the 0.01 mg/L "no-action" proposed for lead was exceeded in 43% of the samples and 62% of the samples exceeded the current 1.0 mg/L MCL standard for copper. In single-family house samples, these values were
1 Compliance with the proposed 0.01 mg/L no action limit for lead is based on a sample average.
Individual samples may exceed this value and still be in compliance. 47% and 73%, respectively. The average lead concentration for all high-rise samples was 0.020 mg/L and 0.013 mg/L for house samples. Regulatory levels stated above would still be exceeded in 6% of the cases for lead and 9% of the cases for copper, even after prolonged flushing of the tap in a high-rise building. In all cases associated with single-family houses, flushing the cold water tap for 5 minutes was successful in achieving compliance levels.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Ballantyne, Brian Andrew, and n/a. "�This must be the place� : plumbing a land ethic for the built environment." University of Otago. Department of Surveying, 1995. http://adt.otago.ac.nz./public/adt-NZDU20070531.140040.
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A land ethic within the built enviroment was examined from the perspective of the surveying community in New Zealand. The research followed a structure of context, interpretation and application; used legal analysis; and, sampled the ideologies of iwi liason officers, consultant surveyors, and local authorities.
Context involved asking why a land ethic was being debated, by focusing on the current level of environmental thought, and on the actions of the International Federation of Surveyors (FIG) and the New Zealand Institute of Surveyors (NZIS). Some findings are: that terms such as sustainable management and nature are ambiguous cultural constructs; and, that the adoptation of an environmental policy by the NZIS continues to be a tortuous process.
Interpretation involved asking what constituted a New Zealand ethic, by putting such an ethic into perspective in relation to ecophilosophy, and by searching for a contemporary sense of kaitiakitanga. Some findings are: that restraint and humility are requirements in any moral theory of nature; that kaitiakitanga is not dependent on title to land; and, that iwi liason officers are divided as to how kaitiakitanga applied to the built environment.
Application involved suggesting how a land ethic could be invoked in the built environment, through the provision of green space in the form of local purpose reserves. Some findings are: that surveyors regard reserves as being significantly less vital to a community�s well-being than engineered services; and, that local authorities are not generally aware that reserve policies might have to be linked to municipal open space strategies.
The broad conclusions are: that regardless of the environment that now exists, surveyors will be required to make moral choices about the environment that is sought; that a land ethic will not necessarily provide rational prescriptions directing action towards land; and, that there is inherent tension between land tenure, land use and a land ethic. Suggested avenues for further research include a comparative analysis of other landed professions; the empowerment of women within any land ethic; and, the use of content analysis as an alternative methodology.
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Mundkur, Anuradha. "Let's fix the plumbing. Information technology and bureaucratic reform a case from India /." Related electronic resource:, 2007. http://proquest.umi.com/pqdweb?did=1342729451&sid=1&Fmt=2&clientId=3739&RQT=309&VName=PQD.
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Terry, Jason. "Incorporating mechanical, electrical and plumbing systems into historic preservation projects : three case studies." Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/803.
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Farooqi, Owais Ehtisham. "An Assessment and Modeling of Copper Plumbing pipe Failures due to Pinhole Leaks." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/33918.
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Pinhole leaks in copper plumbing pipes are a big concern for the homeowners. The problem is spread across the nation and remains a threat to plumbing systems of all ages. Due to the absence of a single acceptable mechanistic theory no preventive measure is available to date. Most of the present mechanistic theories are based on analysis of failed pipe samples however an objective comparison with other pipes that did not fail is seldom made. The variability in hydraulic and water quality parameters has made the problem complex and unquantifiable in terms of plumbing susceptibility to pinhole leaks.
The present work determines the spatial and temporal spread of pinhole leaks across United States. The hotspot communities are identified based on repair histories and surveys. An assessment of variability in water quality is presented based on nationwide water quality data. A synthesis of causal factors is presented and a scoring system for copper pitting is developed using goal programming. A probabilistic model is presented to evaluate optimal replacement time for plumbing systems. Methodologies for mechanistic modeling based on corrosion thermodynamics and kinetics are presented.Master of Science
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Rhoads, William J. "Growth of Opportunistic Pathogens in Domestic Plumbing: Building Standards, System Operation, and Design." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/76653.
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Understanding and limiting public health threats resulting from exposure to opportunistic pathogens (OPs) in domestic water (i.e., hot/cold water for human use) will be one of the grand challenges for water safety in the 21st century. This dissertation anticipates some of the complexities in balancing stakeholder goals and developing building standards to limit OP growth, and advances scientific understanding of OP survival and proliferation in domestic plumbing systems.
In a cross-sectional survey of water- and energy-efficient buildings, domestic water age ranged from 8 days to 6 months and resulted in pH and temperature fluctuations, rapid disinfectant residual decay up to 144 times faster than municipal water delivered to the buildings, and elevated levels of OP gene markers. This motivates future work to determine how to maintain high quality and safe water while preserving the sustainability goals of these cutting-edge buildings.
Head-to-head pilot-scale experiments examining OP growth in recirculating hot water systems revealed that elevated temperature had an overarching inhibitory effect on L. pneumophila growth where temperatures were maintained. However, control was undermined in distal branches, especially when density-driven convective mixing gradients maintained ideal growth temperatures and delivered nutrients to the otherwise stagnant branches. These results resolve discrepancies reported in the literature regarding the effects of flow, and identify important system design and operational conditions that facilitate OP growth.
Advancements were also made in understanding how corrosion can trigger OP growth. In Flint, MI, corrosive Flint River water damaged iron pipes, releasing iron nutrients, consuming chlorine residual, and supporting high levels of L. pneumophila in large building systems. This likely triggered two unprecedented clusters of Legionnaire's disease.
In pilot-scale systems, copper released from copper pipes, but not dosed as soluble cupric, triggered release of >1,100 times more H2 into the water due to deposition corrosion. The organic carbon fixed by autotrophic hydrogen oxidation has the potential to facilitate OP growth, but more work is needed to understand the limits of this mechanism.
Finally, well-controlled laboratory experiments confirmed past reports from field surveys that the use of chloramines trigger a trade-off between controlling Legionella and allowing non-tuberculous Mycobacteria to persist.Ph. D.
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Zhang, Yan. "Nitrification in premise plumbing and its effect on corrosion and water quality degradation." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26943.
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Nitrification is increasingly of concern in US potable water systems, due to changes from chlorine to chloramine as a secondary disinfectant in order to comply with new regulations for disinfectant by-products. The ammonia that is released from the chloramine decay supports nitrification.
A comprehensive literature review systematically examined the complex inter-relationships between nitrification, materials corrosion and metals release. That analysis suggested that nitrification could accelerate decay of chloramine, enhance corrosion of water distribution system materials, and increase leaching of lead and copper to potable water under at least some circumstances. Moreover, that certain plumbing materials would inhibit nitrification, but that in other situations the plumbing materials would enhance nitrification.
Experiments verified that nitrification could affect the relative efficacy of chlorine versus chloramine in controlling heterotrophic bacteria in premise plumbing. Without nitrification, chloramine was always more persistent and effective than chlorine in controlling biofilms. But with nitrification and in pipe materials that are relatively non-reactive with chlorine, chloramine was much less persistent and less effective than chlorine. In materials that are reactive with chlorine such as iron pipes, the relative efficacy of chloramine versus chlorine depends on the relative rate of corrosion and rate of nitrification. High rates of corrosion and low rates of nitrification favor the use of chloramine versus free chlorine in controlling bacteria.
Plumbing materials had profound impacts on the incidence of nitrification in homes. Effects were due to toxicity (i.e., release of Cu⁺²), recycling of nitrate back to ammonia substrate by reaction (zero-valent iron, lead or zinc materials), or release of nutrients that are essential to nitrification by leaching from concrete or other materials. As a general rule it was determined that concrete and iron materials encouraged growth of nitrifiers in certain oligotrophic waters, materials such as lead, PVC/plastic pipe, glass and surfaces of other materials were readily colonized by nitrifiers, and materials such as copper and brass were very toxic and relatively resistant to nitrifier colonization.
Dependent on circumstance, nitrification had no effect, increased or decreased aspects of materials corrosion. Nitrification markedly increased lead contamination of low alkalinity potable water by reducing the pH. In some cases nitrification dramatically decreased leaching of zinc to potable water from galvanized iron, because of lowered dissolved oxygen and reduced pH. Nitrification did not affect copper solubility in low alkalinity water, but is expected to increase copper solubility in higher alkalinity waters. Finally, nitrification in homes plumbed with PVC or plastics can drop the pH and increase leaching of lead from downstream brass materials in faucets. This can explain why some modern homes plumbed with PVC can have more lead in water when compared to homes plumbed with copper pipe.
Phosphate had profound impacts on the incidence of nitrification and resulting effects on water quality. While phosphate levels below about 5 ppb could strongly inhibit nitrification due to a nutrient limitation, nitrifiers can obtain sufficient phosphate from plastic, concrete, copper and iron pipe materials to meet nutritional needs. High levels of phosphate inhibitor can reduce the concentration of Cu⁺² ions and make nitrification more likely, but phosphate can also sometimes lower the corrosion rate and increase the stability of disinfectant and its efficacy in controlling nitrifiers. Phosphate plays a key role in determining where, when and if problems with nitrification will occur in a given water distribution system.
This work provides some new fundamental and practical insights to nitrification issues through a comprehensive literature review, lab experiments, solubility modeling and field studies. The results and practical tools developed can be used by utilities and consumers to predict nitrification events and resulting water quality problems, and to make rational decisions about practices such as inhibitor dosing, plumbing material selection and use of whole house filters.Ph. D.
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Maia, Ana. "Controls on shallow plumbing systems inferred from the spatial analysis of pockmark arrays." Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/111446/.
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In marine geological settings, pockmarks are evidence of highly focused fluid expulsion at the seabed. The modern seafloor of the Lower Congo Basin (LCB, offshore West Africa) is covered by densely packed arrays of thousands of pockmarks, whose distribution reflects in part the spatial organization of underlying seal bypass features. This study describes and analyses the variable distributions of seabed pockmarks using 3D seismic and spatial statistics, in order to infer subsurface processes that control the fluid migration routes and understand the overall shallow plumbing system of the area. The 3D seismic visualization of feeding conduits (pipes) allowed the identification of the source interval for the fluids expelled during pockmark formation. Pockmark formation may be linked to gas hydrate dissociation and/or expulsion of free gas beneath the GHSZ. Spatial statistics were used to show the relationship between underlying discontinuities and seabed pockmarks distributions, and revealed that pockmark occurrence is not considered to be random. Several different types of geo-mechanical controls were recognised and divided into 1) stratigraphic or depositional controls, 2) strati-structural controls, and 3) structural controls, corresponding to increasing stages of deformation affecting basin sediments. Furthermore, from the wide variability of pockmark sizes present in the area and the local geomorphology, it is possible to conclude that pockmark size is related 1) to the sub-surface depth at which the fluid source interval occurs and 2) to lateral variations of the degree of overpressure. The results of this study are relevant for the understanding of shallow fluid plumbing systems in offshore settings, with implications on our current knowledge of overall fluid flow systems in hydrocarbon-rich continental margins. This is relevant for the understanding of shallow fluid plumbing systems in offshore settings and overall fluid flow systems in hydrocarbon-rich continental margins.
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Dahrén, Börje. "Investigating Magma Plumbing Beneath Anak Krakatau Volcano, Indonesia : Evidence for Multiple Magma Storage Regions." Thesis, Uppsala universitet, Berggrundsgeologi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-137309.
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Improving our understanding of magma plumbing and storage remains one of the majorchallenges for petrologists and volcanologists today. This is especially true for explosivevolcanoes, where constraints on magma plumbing are essential for predicting dynamicchanges in future activity and thus for hazard mitigation. This study aims to investigate themagma plumbing system at Anak Krakatau; the post-collapse cone situated on the rim of the1883 Krakatau caldera. Since 1927, Anak Krakatau has been highly active, growing at a rateof ~8 cm/week. The methods employed are a.) clinopyroxene-melt thermo-barometry (Putirkaet al., 2003; Putirka, 2008), b.) plagioclase-melt thermo-barometry (Putirka, 2005), c.)clinopyroxene composition barometry (Nimis & and Ulmer, 1998; Nimis, 1999; Putirka,2008) and d.) olivine-melt thermometry (Putirka et al., 2007). Previously, both seismic(Harjono et al., 1989) and petrological studies (Camus et al., 1987; Mandeville et al., 1996a;Gardner et al., in review, J. Petrol.) have addressed the magma plumbing beneath AnakKrakatau. Interestingly, petrological studies indicate shallow magma storage in the region of2-8 km, while the seismic evidence points towards a mid-crustal and a deep storage, at 9 and22 km respectively.This study shows that clinopyroxene presently crystallizes in a mid-crustal storage region(8-12 km), a previously identified depth level for magma storage, using seismic methods(Harjono et al., 1989). Plagioclases, in turn, form at shallower depths (4-6 km), in concertwith previous petrological studies (Camus et al., 1987; Mandeville et al., 1996a; Gardner etal., in review, J. Petrol.). Pre-1981 clinopyroxenes record deeper levels of storage (8-22 km),indicating that there may have been an overall shallowing of the plumbing system over thelast ~40 years. The magma storage regions detected coincide with major lithologicalboundaries in the crust, implying that magma ascent and storage at Anak Krakatau is probablycontrolled by crustal discontinuities and/or density contrasts. Therefore, this study shows thatpetrology has the sensitivity to detect magma bodies in the crust where seismic surveys faildue to limited resolution. Combined geophysical and petrological surveys offer an increasedpotential for the thorough characterization of magma plumbing at active volcanic complexes.
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Budd, David A. "Characterising volcanic magma plumbing systems : A tool to improve eruption forecasting at hazardous volcanoes." Doctoral thesis, Uppsala universitet, Mineralogi, petrologi och tektonik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-267473.
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This thesis attempts to develop our understanding of volcanic magma plumbing systems and the magmatic processes that operate within them, such as fractional crystallisation, crustal partial melting, assimilation, and magma mixing. I utilise petrology, rock and mineral geochemistry, and isotope systematics to seek to improve our ability to forecast the eruptive frequency and style of active volcanoes, an aspect often lacking in current volcano monitoring efforts. In particular, magma reservoir dynamics are investigated from a mineral scale at Katla volcano in Iceland, to a sub-mineral scale at Merapi, Kelud, and Toba volcanoes in Indonesia. The magma plumbing architecture of Katla volcano on Iceland is explored in the first part of this thesis. Crystalline components within tephra and volcanic rock preserve a record of the physical and chemical evolution of a magma, and are analysed through oxygen isotopic and thermobarometric techniques to temporally constrain changes in reservoir depth and decode the petrogenesis of the lavas. We find both prolonged upper crustal magma storage and shallow level assimilation to be occurring at Katla. The results generated from combining these analytical strands reveal the potential for unpredictable explosive volcanism at this lively Icelandic volcano. The second part of this thesis examines the magma plumbing systems of Merapi, Kelud and Toba volcanoes of the Sunda arc in Indonesia at higher temporal and petrological resolution than possible for Katla (e.g., due to the crystal poor character of the rocks). For this part of the thesis, minerals were analysed in-situ to take advantage of sub-crystal scale isotopic variations in order to investigate processes of shallow-level assimilation in the build-up to particular eruptions. We find that intra-crystal analyses reveal an otherwise hidden differentiation history at these volcanoes, and establish a better understanding as to how they may have rapidly achieved a critical explosive state. The outcomes of this thesis therefore deepen our knowledge of evolutionary trends in magma plumbing system dynamics, and highlight the importance of understanding the geochemical processes that can prime a volcano for eruption. Lastly, I emphasise the vital contribution petrology can make in current volcano monitoring efforts.
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Durand, Monique Lucia. "Disinfectants and Plumbing Materials: Effects on the Sensory and Chemical Characteristics of Drinking Water." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/35861.
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The distribution system is the primary cause of taste and odor complaints in drinking water. This research examined the ability of small diameter pipes used in home plumbing to affect drinking water quality. The properties of the materials were investigated in the absence of disinfectant and the presence of either chlorine or chloramines. A panel was trained in flavor profile analysis (FPA) according to Standard Methods 2170B and used to assess the sensory properties of all samples. Chemical analyses were performed to determine disinfectants, total organic carbon (TOC), pH and specific organic contaminants.
The first part of this study investigated PEX pipes manufactured by the silane (PEX-b) and peroxide (PEX-a) cross-linking technology, using the utility quick test (UQT) method. Silane PEX-b had a greater effect on water quality properties such as odor, TOC and residual disinfectant demand than peroxide-linked PEX-a. Chemical analysis revealed that PEX pipes can contribute fuel oxygenates such as ETBE (PEX-b) and possibly MTBE (PEX-a) to drinking water. PEX pipes did not contribute any significant trihalomethanes to drinking water. This study showed that the type of PEX used in homes will determine the extent to which drinking water quality is affected.
The second part of this study used simulated plumbing rigs to investigate seven different materials under low flow and stagnant conditions; chlorinated polyvinyl chloride, cross-linked polyethylene, polyethylene, epoxy-lined copper, copper, stainless steel, galvanized iron and glass (control). Results showed that these plumbing materials have the potential to affect water quality characteristics such as TOC concentrations, residual disinfectant and odor when newly installed in homes. A high TOC concentration was consistent with the presence of a distinct odor or a high FPA intensity rating. Galvanized iron produced the worst odors that were consistently described as "motor oil". Polyethylene generated more intense plumbing associated odors than PEX or cPVC plastic material. cPVC and copper generated the least odors. Both copper pipe and epoxy-lined copper consumed residual chlorine and chloramines.Master of Science
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Lee, Kin-wang. "A comparative study of the life cycle cost of mechanical building services installations based on different maintenance strategies /." View the Table of Contents & Abstract, 2006. http://sunzi.lib.hku.hk/hkuto/record/B38026594.
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