Safe drinking water is paramount to a healthy society. Close to a hundred contaminants are regulated by the government. Utilities are using chloramines to disinfect water to reduce harmful byproducts that may present themselves with the use of chlorine alone. Using chlorine and ammonia to disinfect, ammonia oxidizing bacteria can present themselves in an unsuspecting utilities distribution network. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

Four-dimensional variational data assimilation (4D-Var) provides an estimate to the state of a dynamical system through the minimization of a cost functional that measures the distance to a prior state (background) estimate and observations over a time window. The analysis fit to each information input component is determined by the specification of the error covariance matrices in the data assimilation system (DAS). Weak-constraint 4D-Var (w4D-Var) provides a theoretical framework to account for modeling errors in the analysis scheme. In addition to the specification of the background error covariance matrix, the w4D-Var formulation requires information on the model error statistics and specification of the model error covariance. Up to now, the increased computational cost associated with w4D-Var has prevented its practical implementation. Various simplifications to reduce the computational burden have been considered, including writing the model error covariance as a scalar multiple of the background error covariance and modeling the model error. In this thesis, the main objective is the development of computationally feasible techniques for the improved representation of the model error statistics in a data assimilation system. Three new approaches are considered. A Monte Carlo method that uses an ensemble of w4D-Var systems to obtain flow-dependent estimates to the model error statistics. The evaluation of statistical diagnostic equations involving observation residuals to estimate the model error covariance matrix. An adaptive tuning procedure based on the sensitivity of a short-range forecast error measure to the model error DAS parametrization. The validity and benefits of these approaches are shown in two stages of numerical experiments. A proof-of-concept is shown using the Lorenz multi-scale model and the shallow water equations for a one-dimensional domain. The results show the potential of these methodologies to produce improved state estimates, as compared to other approaches in data assimilation. It is expected that the techniques presented will find an extended range of applications to assess and improve the performance of a w4D-Var system.

No description available.

In recent years, many construct wetlands in Taiwan have been built for the purposes of wastewater treatment, river water purification, and ecology conservation. To evaluate the effectiveness of constructed wetlands on water purification, frequent water quality monitoring is needed. In this study, the multivariate statistical analysis was applied to evaluate the contaminant removal efficiency in a constructed wetland, and the time series method was then used to predict the trend of the indicative pollutant concentration in the wetland. Multivariate statistical analysis simplifies the original data into representative factors, or hive off the similarity between data to cluster, and then identify clustering outcomes. In this study, an artificial wetlands at the site around an old bridge locates at the Kaoping River Basin was used as the study site. The statistical software SPSS 12.0 was used to perform the multivariate statistical analysis to evaluate water quality characteristics of its. Results from this study show that the removal efficiency for the total coliforms (TC) of System A and B was 98%, 55% for biochemical oxygen demand (BOD), 53% for chemical Oxygen demand (COD), 55% for ammonia nitrogen (NH3-N), and 39% for total nitrogen (TN). Moreover, suspended solids (SS) couldn¡¦t be removed in both A and B systems. The box-and-whisker plot indicates that the water quality of inflow was unstable and variable; however, outflow was turning stable with its flow direction. The major pollutant indicators, except SS, were all in a decreasing tendency. The paired t-test shows p value of each item were lower than 0.05, except total phosphorus (TP) in System A, nitrate nitrogen (NO3-N) and Chlorophyll a (Chl-a) in System B. The correlation parameters from TN, nitrogen oxides (NOx), NO3-N and nitrite nitrogen (NO2-N) and so on were all higher than 0.7. The factor analysis of SPSS shows that 17 water-quality items of the study site could obtain four to six principal components, including nitrate nutrition factor, phosphorus nutrition factor, eutrophication factor, organic factor, and environmental background factor, the major influencing components are nutrition factor and eutrophication factor. The ponds of the study site were classified into two or three clusters depend on in-and-out flow location. This study attempted to establish a forecasting model of wetland pollutants concentration through the time series (ARIMA), results show that the outcome of the B7 pond was better than others. Results indicate that the ARIMA model can be used to simulate the trend of treatment efficiency using the wetland system. Experience and results obtained from this study would provide solutions for water quality control.

Due to limitation of economics and legislation, the power system is not allowed serious accident on modern social. In order to enhance system reliability, many types of special protection systems (SPS) have been implemented by utilities around the world. One of the main concerns in the design of an SPS is whether the designed system can achieve the reliability requirement. Currently, the literature that discusses the SPS reliability issue is scarce. In this thesis, a comparison of several techniques suitable for performing reliability assessment of SPS is presented. Discussed reliability models include using reliability block diagram, fault tree analysis, Markov modeling and Monte Carlo simulations. In order to understand the uncertainty effects of input data on the calculated system reliability, Monte Carlo Sampling method is utilized in this study to take the input parameters uncertainty into account in the system modeling. To deal with the problem of not being able to reach the reliability requirement after uncertainty analysis, a sensitivity analysis is proposed to analyze the importance of the components involved in the system. Sensitivity analysis can be used to identity the most effective component in the enhancement the SPS reliability. A Taipower SPS is used in this thesis to explain the proposed reliability assessment methods.

Thesis (Ph.D.)--University of Oklahoma, 1991. / Includes bibliographical references (leaves 148-153).

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

The electrochemical detector provides a promising detection mode for capillary electrophoresis (CE) due to its excellent sensitivity, good portability, high selectivity, easy miniaturization, low capital and running cost. To widen its scope for determining trace analytes in complex samples, three dual-electrode detectors were fabricated to enable the determination of electro-inactive analytes, to assess co-eluted peaks and to give a large enhancement of the detection sensitivity by modifying electrode surface using multi-walled carbon nanotubes (MWNTs). To determine trace non-electroactive amino acids present in human tears, a serial dual-electrode detector was developed using an upstream on-capillary Pt film electrode to oxidize bromide to bromine at +1.0 V and a downstream Pt disk electrode to detect the residual bromine at +0.2 V after their reaction with amino acids eluted out from the separation capillary. The bromide reagent was introduced after CE separation by a newly designed coaxial post-column reactor fabricated onto the PMMA chip. Using optimized CE buffer containing 20 mM borate, 20 mM SDS at pH 9.8, L-glutamine, L-alanine and taurine were baseline separated with detection limits ranging from 0.56-0.65 μM and a working range of 2-200 μM for L-glutamine and of 2-300 μM for both L-alanine and taurine. Method reliability was established by close to 100% recoveries for spiked amino acids and good agreement between the measured and the literature reported amino acid concentrations in tears. For the determination of polyphenols in wine, a microchip-CE device was fabricated with a dual-opposite carbon fiber microelectrode operated in a parallel mode to assess peak purity. Under optimized conditions, (+)-catechin, trans-resveratrol, quercetin, (-)-epicatechin and gallic acid were baseline separated within 16 min with detection limits ranging from 0.031- 0.21 mg/L and repeatability of 2.0-3.3 % (n=5). The use of an opposite dual-electrode enables the simultaneous determination of peaks and measurement of their current ratios at +0.8 V and +1.0 V vs Ag/AgCl. The capability of using current ratio to identify the presence of co-migrating impurities was demonstrated in a mixed standard solution with overlapping (+)-catechin and (-)-epicatechin peaks and in a commercial red wine with interfering impurities. Matching of both the migration time and the current ratio reduce false positive and validate polyphenol quantitation in red wine. Lastly, a dual-opposite MWNTs modified carbon fiber microelectrode (CFME) was developed to determine the biomarkers (4-nitrophenol, 4-nitrophenyl-glucuronide and 4-nitrophenyl-sulfate) needed to assess exposure to methyl parathion. Use of the MWNTs modified CFME showed a much higher sensitivity than bare CFME, with a detection limit of 0.46 μM for 4-nitrophenol. Baseline separation of all three biomarkers was obtained within 31 min by a 45 cm long capillary under 12 kV in a 20 mM phosphate buffer at pH 7.0. The method developed was successfully utilized to determine low levels of biomarkers in human urine without using complex pretreatment steps and delivered recoveries ranging from 95.3 - 97.3% and RSDs within 5.8% (n=3). Using a parallel dual-electrode detector was shown to deliver reliable results with matching current ratios and comparable migration time to those obtained from biomarker standards. / published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / toc / Statistics and Actuarial Science / Master / Master of Philosophy

The core-logger has been designed for the high-resolution radiometric analysis of soil cores using multiple detectors. This device allows for the automation of the measuring process and eliminates the need to dissect the cores. The design is aimed at measuring soil-cores with a 10cm radius and a length of 1m and allows for up to 4 detectors to be mounted on the measuring platform. Currently a combination of Bismuth-German.te (BGO) and C.esiwn-Iodide (CsI) detectors are used. The core logger required a good spatial resolution of - 1 cm. This has been difficult to obtain and has required extensive investigation. The shielding configurations were varied and the effect of background radiation was looked at in detail to determine an optimal construction. A secondary objective has been the complete measurement of a single core in 24 hours. This has also been difficult to achieve because the low activity of natural radiation in the core samples needs longer measuring times. The BGO detectors were used as a more efficient detector (than, e.g. CsI) which helped to reduce the required measuring time. Measured spectra have been analysed to determine the activity concentrations of the specific radionuclides of interest: 232Th, 238U, 40K and 137Cs. These activity profiles of the measured cores provide information that can then be used to radiometrically fingerprint the sample to determine soil characteristics such as grain size and mineral content. However, because the actual resolution of the system ( ~3cm) is greater than the typical core slice (~ 2cm), the radiometric information in a specific core-slice contains contributions from its adjacent slices. This folding or convolution of the measured spectra can be undone using a deconvolution method. which was examined and commented on. / Thesis (M.Sc.)-University of Natal, Durban, 2001.