938 resultados para Water in oil emulsion


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Johannes Vermeer; 1 ft. 5 63/64 in.x 1 ft. 3 63/64 in.; oil on canvas

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Claude Monet; 3 ft. 3 49/64 in.x 6 ft. 6 47/64 in.; oil on canvas

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Tracking the movement of migratory freshwater fish is essential to those invested in rebuilding declining fish populations. Using strontium isotopic signatures to match calcified fish tissues to streams where fish spawn is a useful method of tracking migratory fish where physical tracking methods such as radio, acoustic, or external tags, have proven unsuccessful. In this study, we develop tools to practice this method of tracking fish in Lake Roosevelt and its upstream tributaries in Washington State by analyzing the elemental concentrations and 87Sr/86Sr ratios of water samples, and mussel shell samples. This study evaluates whether mussel shells act as an appropriate proxy for water chemistry by comparing the 87Sr/86Sr isotope ratios of water samples to the 87Sr/86Sr isotope ratios of mussel shells sampled from the same, or nearby, locations. We compare concentrations of Ba, Ca, Cd, Cu, Fe, Mg, Pb, Sr, and U in the water and mussel shell samples to determine the feasibility of using mussel shells as a proxy for water chemistry. If it is determined that the concentrations of these elements in mussel shells reflect that of the surrounding water composition, the elemental composition of mussel shells can be compared to that of calcified tissues in fish, such as otoliths, to infer the location of the natal stream. We report analyses of water and mussel shell samples collected from Lake Roosevelt, Sanpoil River, Spokane River, Colville River, Kettle River, Pend Oreille River, Kootenay River, and Columbia River in Washington State. Each of these rivers is a tributary to Lake Roosevelt, and each flows through different geologic units. We hypothesize that the differences in the rock units of each stream’s watershed are reflected in the elemental concentrations and strontium isotopic ratios of water in each stream and in the lake. We also hypothesize that the composition of the mussel shells will match the composition of the water samples, therefore allowing us to use the mussel shells as a proxy for local water chemistry. Additionally, we hypothesize that the composition of the mussel shells will vary by location, and that we will be able to then infer where a fish is from by matching the composition of the fish in question to the mussels we have analyzed. We found that 87Sr/86Sr values for water and mussel hinge samples collected from tributaries east of Lake Roosevelt are significantly higher than the 87Sr/86Sr values for samples collected from tributaries west of Lake Roosevelt with averages of 0.7235 and 0.7089, respectively. The average 87Sr/86Sr ratios for water and mussel hinge samples collected within Lake Roosevelt is 0.7158, which is between the averages for samples collected east and west of the lake. Generally, older rocks are exposed on the east side of the lake, and younger rocks on the west side of the lake, so our 87Sr/86Sr values support the hypothesis that geologic units are a primary control on water chemistry, and that tributary compositions mix to form an average weighed by flow in Lake Roosevelt. The 87Sr/86Sr values for water and mussel shell samples collected from the same locations have a strong, positive linear correlation, suggesting that mussel shell 87Sr/86Sr ratios reflect the 87Sr/86Sr ratios of the ambient water. With these data, we can distinguish between different streams and the lake, but cannot distinguish between samples from within the same stream or within Lake Roosevelt. The Sr:Ca and Fe:Ca ratios of water samples show positive correlations with mussel shell compositions, with R2 values of 0.82 and 0.52, respectively. Ratios of Mg, Ba, Cu, Cd, Pb, and U to Ca showed little or no positive correlation between water and mussel shell samples. The elemental concentration data collected for this study do not demonstrate whether a correlation between elemental ratios in water samples and elemental ratios in mussel shell samples collected from the same location exists. Positive Sr:Ca and Fe:Ca correlations for water versus mussel shell samples indicate that perhaps for some elements, the composition of mussel shells are representative of the composition of ambient water. Using elemental concentration ratios to complement 87Sr/86Sr isotopic data may enhance our ability to identify correlations between water and mussel shell samples, and ultimately between mussel shell and otolith samples. The hinge part of a mussel shell may be used as a proxy for local water composition because the mussel shell composition reflects that of the local ambient water. The hinge of the mussel has the same composition as the whole mussel shell. We measured variation of 87Sr/86Sr ratios in the water among different streams and Lake Roosevelt. The 87Sr/86Sr values for samples collected in tributaries east of Lake Roosevelt, which erode older rocks, are higher for mussel shell and water samples than the average 87Sr/86Sr values for mussel shell and water samples collected in tributaries west of Lake Roosevelt, which flow through younger rocks.

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Thesis (Ph.D.)--University of Washington, 2016-06

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In this paper, we study the performance of smallholders in a nucleus estate and smallholder (NES) scheme in oil palm production schemein West Sumatra by measuring their technical efficiency using a stochastic frontier production function. Our results indicate a mean technical efficiency of 66%, which is below what we would have expected given the uniformity of the climate, soils and plantation construction among the sample farmers. The use of progressive farmers as a means of disseminating extension advice does not appear to have been successful, and more rigorous farmer selection procedures need to be put in place for similar schemes and for general agricultural extension in future. No clear relationship was established between technical efficiency and the use of female labour, suggesting there is no need to target extension services specifically at female labourers in the household. Finally, education was found to have an unexpectedly negative impact on technical efficiency, indicating that farmers with primary education may be more important than those with secondary and tertiary education as targets of development schemes and extension programs entailing non-formal education. (C) 2003 Elsevier Ltd. All rights reserved.

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Water recovery is one of the key parameters in flotation modelling for the purposes of plant design and process control, as it determines the circulating flow and residence time in the individual process units in the plant and has a significant effect on entrainment and froth recovery. This paper reviews some of the water recovery models available in the literature, including both empirical and fundamental models. The selected models are tested using the data obtained from the experimental work conducted in an Outokumpu 3 m(3) tank cell at the Xstrata Mt Isa copper concentrator. It is found that all the models fit the experimental data reasonably well for a given flotation system. However, the empirical models are either unable to distinguish the effect of different cell operating conditions or required to determine the empirical model parameters to be derived in an existing flotation system. The model developed by [Neethling, SJ., Lee, H.T., Cilliers, J.J., 2003, Simple relationships for predicting the recovery of liquid from flowing foams and froths. Minerals Engineering 16, 1123-1130] is based on fundamental understanding of the froth structure and transfer of the water in the froth. It describes the water recovery as a function of the cell operating conditions and the froth properties which can all be determined on-line. Hence, the fundamental model can be used for process control purposes in practice. By incorporating additional models to relate the air recovery and surface bubble size directly to the cell operating conditions, the fundamental model can also be used for prediction purposes. (C) 2005 Elsevier Ltd. All rights reserved.

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Phase diagrams of the pseudoternary systems ethyloleate, polyoxyethylene 20 sorbitan mono-oleate/sorbitan monolaurate and propylene glycol with and without butanol as a co-surfactant were prepared. Areas containing optically isotropic, one-phase systems were identified and samples therein designated as droplet, bicontinuous or solution type microemulsions using conductivity, viscosity and self-diffusion NMR. Nanoparticles were prepared by polymerization of selected microemulsions with ethyl-2-cyanoacrylate and the morphology of the particles was investigated. Addition of monomer to all types of microemulsions led to the formation of nanoparticles, which had an average size of 244 +/- 25 nm, an average polydispersity index of 0.15 +/- 0.04 and a zeta-potential of -17 +/- 3 mV. The formation of particles from water-free microemulsions of different types is surprising, particularly considering that polymerization is expected to occur at a water-oil interface by base-catalysed polymerization. It would appear that propylene glycol is sufficiently nucleophilic to initiate the polymerization. The use of water-free microemulsions as templates for the preparation of poly (alkylcyanoacrylate) nanoparticles opens up interesting opportunities for the encapsulation of bioactives which do not have suitable properties for encapsulation on the basis of water-containing microemulsions.

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In the Mekong region, most paddies in rainfed lowland rice (Oryza sativa L.) lie in a sequence on gentle sloping land, and grain yield (GY) often depends on the toposequence position. There is, however, lack of information on toposequential effects on field water supply in rainfed lowland rice and how that influences GY. A total of eight field experiments were carried out on sandy, coarse-textured soils in Southern Laos (Champassak Province and Savannakhet Province) over three wet seasons (2000-2002). Components of the water balance, including downward and lateral water movement (D and L, respectively), were quantified at three different positions along toposequences (top, middle and bottom). GY, days-to-flower (DTF) and rainfall were measured, and the water productivity (WP) was determined. In most experiments, standing water disappeared first in the top position and gradually in lower positions. This was associated with the observation that when there was standing water in the field, the higher position had larger D in both the provinces and also larger L in Champassak Province. However, in one experiment, water loss appeared later in the higher position, as the result of lower L, apparently due to some water inputs other than rainfall occurring at this position. Despite larger D plus L at the top position, seasonal sum of D and L were not much affected by the toposequence position, as the daily rate of D plus L became minimal when the standing water was lost earlier in the top position. Lower GY was associated with earlier disappearance of standing water from the field. Relatively low GY was expected in the top toposequence position. This was clearly shown in the toposequence of Phonthong, Champassak Province, as the timing of standing water disappearance relative to flowering was earlier in the top position. Variation in GY across the toposequence positions was coupled with the WP variation, and both GY and WP tended to decline with increased DTF. Therefore, variation in productivity of rainfed lowland rice across toposequence positions depends mainly on the field water status around flowering time. (c) 2005 Elsevier B.V. All rights reserved.

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The literature relating to the performance of pulsed sieve plate liquid-liquid extraction columns and the relevant hydrodynamic phenomenon have been surveyed. Hydrodynamic behaviour and mass transfer characteristics of droplets in turbulent and non-turbulent conditions have also been reviewed. Hydrodynamic behaviour, i.e. terminal and characteristic velocity of droplets, droplet size and droplet breakup processes, and mass transfer characteristics of single droplets (d≤0.6 cm) were investigated under pulsed (mixer-settler & transitional regimes) and non-pulsed conditions in a 5.0 cm diameter, 100 cm high, pulsed sieve plate column with three different sieve plate types and variable plate spacing. The system used was toluene (displaced) - acetone - distilled water. Existing photographic techniques for following and recording the droplet behaviour, and for observing the parameters of the pulse and the pulse shape were further developed and improved. A unique illumination technique was developed by which a moving droplet could be photographed using cine or video photography with good contrast without using any dye. Droplet size from a given nozzle and droplet velocity for a given droplet diameter are reduced under pulsing condition, and it was noted that this effect is enhanced in the presence of sieve plate. The droplet breakup processes are well explained by reference to an impact-breakup mechanism. New correlations to predict droplet diameter based on this mechanism are given below.vskip 1.0cm or in dimensionless groups as follows:- (We)crit= 3.12 - 1.79 (Eo)crit A correlation based on the isotropic turbulence theory was developed to calculate droplet diameter in the emulsion regime.vskip 1.0cm Experimental results show that in the mixer-settler and transitional regimes, pulsing parameters had little effect on the overall dispersed phase mass transfer coefficient during the droplet formation and unhindered travel periods.

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Water is a common impurity of jet fuel, and can exist in three forms: dissolved in the fuel, as a suspension and as a distinct layer at the bottom of the fuel tank. Water cannot practically be eliminated from fuel but must be kept to a minimum as large quantities can cause engine problems, particularly when frozen, and the interface between water and fuel acts as a breeding ground for biological contaminants. The quantities of dissolved or suspended water are quite small, ranging from about 10 ppm to 150 ppm. This makes the measurement task difficult and there is currently a lack of a convenient, electrically passive system for water-in-fuel monitoring; instead the airlines rely on colorimetric spot tests or simply draining liquid from the bottom of fuel tanks. For all these reason, people have explored different ways to detect water in fuel, however all these approaches have problems, e.g. they may not be electrically passive or they may be sensitive to the refractive index of the fuel. In this paper, we present a simple, direct and sensitive approach involving the use of a polymer optical fibre Bragg grating to detect water in fuel. The principle is that poly(methyl methacrylate) (PMMA) can absorb moisture from its surroundings (up to 2% at 23 °C), leading to both a swelling of the material and an increase in refractive index with a consequent increase in the Bragg wavelength of a grating inscribed in the material.

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Water is a common impurity of jet fuel, and can exist in three forms: dissolved in the fuel, as a suspension and as a distinct layer at the bottom of the fuel tank. Water cannot practically be eliminated from fuel but must be kept to a minimum as large quantities can cause engine problems, particularly when frozen, and the interface between water and fuel acts as a breeding ground for biological contaminants. The quantities of dissolved or suspended water are quite small, ranging from about 10 ppm to 150 ppm. This makes the measurement task difficult and there is currently a lack of a convenient, electrically passive system for water-in-fuel monitoring; instead the airlines rely on colorimetric spot tests or simply draining liquid from the bottom of fuel tanks. For all these reason, people have explored different ways to detect water in fuel, however all these approaches have problems, e.g. they may not be electrically passive or they may be sensitive to the refractive index of the fuel. In this paper, we present a simple, direct and sensitive approach involving the use of a polymer optical fibre Bragg grating to detect water in fuel. The principle is that poly(methyl methacrylate) (PMMA) can absorb moisture from its surroundings (up to 2% at 23 °C), leading to both a swelling of the material and an increase in refractive index with a consequent increase in the Bragg wavelength of a grating inscribed in the material.

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Why has Corporate Social Responsibility (CSR) yielded such disappointing outcomes in oil-rich sub-Saharan Africa? Over the past decades, a sizable body of literature has emerged which draws attention to the shortcomings of oil-related development and complementary CSR exercises in the region. Most critiques on the topic, however, assess specific interventions and/or policies but fail to evaluate the complex decision-making processes, dictated heavily by setting, which produce such actions altogether. This thesis attributes CSR outcomes in oil-rich sub-Saharan Africa to the unique context in which the decisions underpinning actions take place. In doing so, the analysis borrows ideas from a diverse body of literature spanning the international development, accounting, management and political science disciplines. To explore these ideas further, the thesis focuses on the case of Ghana. The most recent “addition” to sub-Saharan Africa’s oil club, Ghana provides a rare glimpse of how decisions underpinning CSR have been identified, evolved and reshaped from the outset. To provide a comprehensive picture of CSR in the sector and its impacts at the local level, interviews and focus groups were conducted with a range of stakeholder groups. As is the case throughout sub-Saharan Africa, in Ghana, oil production occurs in offshore “enclaves”, which are disconnected geographically from local communities. This thesis argues that these dynamics have important implications for CSR. Findings point to companies also being disconnected ideologically from local development needs, which, in part explains the questionable CSR that has become such a contentious issue in the debate on oil and development in sub-Saharan Africa in recent years. The enclave-type setting in which oil production occurs appears to have stifled creativity and innovation in the area of CSR. This, along with institutional weaknesses, regulatory deficiencies and the Government of Ghana’s failure to adequately respond to local-level concerns, has produced these outcomes.

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This project studied the frequency and of water contamination at the source, during transportation, and at home to determine the causes of contamination and its impact on the health of children aged 0 to 5 years. The methods used were construction of the infrastructure for three sources of potable water, administration of a questionnaire about socioeconomic status and sanitation behavior, anthropometric measurement of children, and analysis of water and feces. The contamination, first thought to be only a function of rainfall, turned out to be a very complex phenomenon. Water in homes was contaminated (43.4%) with more than 1100 total coliforms/100 ml due to the use of unclean utensils to transport and store water. This socio-economic and cultural problem should be ad- dressed with health education about sanitation, The latrines (found in 43.8% of families) presented a double-edged problem. The extremely high population density reduced the surface area of land per family, which resulted in a severe nutritional deficit (15% of the children) affecting mainly young children, rendering them more susceptible to diarrhea (three episodes/child/year).

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The Bahamas is a small island nation that is dealing with the problem of freshwater shortage. All of the country’s freshwater is contained in shallow lens aquifers that are recharged solely by rainfall. The country has been struggling to meet the water demands by employing a combination of over-pumping of aquifers, transport of water by barge between islands, and desalination of sea water. In recent decades, new development on New Providence, where the capital city of Nassau is located, has created a large area of impervious surfaces and thereby a substantial amount of runoff with the result that several of the aquifers are not being recharged. A geodatabase was assembled to assess and estimate the quantity of runoff from these impervious surfaces and potential recharge locations were identified using a combination of Geographic Information Systems (GIS) and remote sensing. This study showed that runoff from impervious surfaces in New Providence represents a large freshwater resource that could potentially be used to recharge the lens aquifers on New Providence.