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Polders (enclosed coastal embankments) are often constructed to protect river and coastal floodplains in deltas. In Bangladesh, a total of 139 polders have been constructed between the 1960s and 1980s to safeguard agricultural lands from potential damage due to tidal floods, storm surge floods, and salinity intrusion. Whilst such flood control measures reduce the probability of flooding, they have had complex impacts on geomorphological and hydrological processes with consequence for human wellbeing. This legacy of interventions in the coastal system and subsequent human adaptations, now makes decision making even more challenging at a time of increasing environmental pressures. This thesis analyses historical floods in the coastal zone in Bangladesh, diagnosing whether the floods were attributable to monsoonal precipitation (pluvial flooding), high upstream river discharge into the tidal delta (fluvio-tidal flooding), or cyclone-induced storm surges. It quantifies polders’ effectiveness by modelling different forms of inundation to estimate what flooding might have been had the polders not been constructed. Considering the societal impacts of flooding, the effects of changing land-use and flood risk on poverty are quantified. The results answer the questions of (i) how the pattern of land use/land cover (LULC) change influences flood risk at present and continue to do so in the future; (ii) how LULC change and flood risk impact poverty spatially. The last section of the thesis focuses on estimating the impacts of potential Tidal River Management (TRM) on elevating the floodplains and reducing the annual probability of flooding. It identifies suitable TRM sites to model sediment deposition in those areas. The potential impact of TRM on flooding is investigated by comparing flood susceptibility ‘before and after’ the implementation of TRM. By analysing complex coastal flood processes and adaptation options spatially and quantitatively, this thesis provides new evidence to the effectiveness of the past (polders), and potential future (TRM) adaptation options. It also presents a new approach to flood risk estimation, considering the societal impacts of flooding. The results of this thesis could be of importance both in research and practice for making scientifically informed decisions on coastal flood risk management, particularly in Bangladesh.

A Quadrupole Mass Spectrometer (QMS) is an instrument for measuring concentrations of atoms and molecules by separating atomic and molecular ions according to their mass-to-charge ratios (m/z). It consists primarily of an ion source, quadrupole mass filter (QMF) and detector. Generally, QMF resolution can be improved by increasing the number of rf cycles of the alternating electric field the ion experiences when passing through the mass filter. In order to improve the resolution, the dimensions of the QMF or the operating parameters are to be changed. However geometric modifications to improve performance increase the manufacturing cost and usually the size of the instrument. A low cost method to increase the resolution of a given QMS is the application of magnetic field to the mass filter. The work is mainly concerned with the performance of a QMS under the influence of magnetic field. Significant improvement in QMS performance was obtained under certain magnetic field conditions, and these have been explained in terms of our theoretical model developed in the University of Liverpool. The theoretical approach assumed in the model is that the QMF contains hyperbolic rods as electrodes and that the magnetic field acts over the full length of the mass filter assembly. This model is capable of accurate simulation of spectra allowing the user to specify different values of mass spectrometer dimensions and applied input signals. The model has been upgraded for better sensitivity, and to simulate the QMF at very high number of rf cycles. Simulation and experimental results were presented for different conditions. This work also demonstrates the modeling of mass spectra of gases using the theoretical model for stability zones 1 and 3. The performance of QMF operating in stability zones 1 and 3 has been derived and a relationship between maximum obtainable resolution and scan line is obtained.

The role of climatic and anthropogenic drivers in groundwater storage depletion and recovery in California’s Central Valley has been investigated. Specifically, the dissertation addresses three research questions: (1) How does climate change impact the groundwater storage? (2) Can managed aquifer recharge (MAR) mitigate groundwater overdraft? (3) How much of the drought-caused groundwater overdraft in Central Valley has recovered during the post-drought years and what is the role of climate and water management in the fast versus slow post-drought overdraft recovery? In the first part of the dissertation, integrated hydrologic models have been simulated to predict future groundwater storage changes under multiple climate change scenarios and to evaluate the relative contribution of crop water use and surface water inflow to Central Valley regions. It is shown that climate change will accelerate groundwater depletion in the future and an increase in future crop water use will be the dominant cause of future groundwater decline without mitigation measure. In the second part, the impact of large-scale MAR implementation on groundwater overdraft recovery, flood peak, and low flow have been investigated via numerical experiments. It is shown that MAR has limited capacity to recovery historical groundwater overdraft due to lack of surface water availability in the southern Central Valley (i.e., San Joaquin and Tulare regions). Delivering excess surface water from the delta to the Tulare and San Joaquin region can significantly solve the groundwater overdraft problem. Moreover, MAR can reduce flood peaks, and increase dry season flow. Finally, an ensemble of groundwater storage change estimates has been made using multiple methods and numerical experiments conducted to understand the role of climate and water management to recover drought-caused groundwater overdraft during post-drought years. The result shows that the Central Valley aquifer is not resilient to drought under existing conditions, and it is very challenging to recover drought-caused groundwater overdraft. However, water management measures that restrict groundwater extraction can significantly reduce the groundwater overdraft recovery time.

Obesity is one of the most prevalent health conditions. About 30% of the world's and over 70% of the United States' adult populations are either overweight or obese, causing an increased risk for cardiovascular diseases, diabetes, and certain types of cancer. Among all cancers, lung cancer is the leading cause of death, whereas pancreatic cancer has the poorest prognosis among all major cancers. Early diagnosis of these cancers can save lives. This dissertation contributes towards the development of computer-aided diagnosis tools in order to aid clinicians in establishing the quantitative relationship between obesity and cancers. With respect to obesity and metabolism, in the first part of the dissertation, we specifically focus on the segmentation and quantification of white and brown adipose tissue. For cancer diagnosis, we perform analysis on two important cases: lung cancer and Intraductal Papillary Mucinous Neoplasm (IPMN), a precursor to pancreatic cancer. This dissertation proposes an automatic body region detection method trained with only a single example. Then a new fat quantification approach is proposed which is based on geometric and appearance characteristics. For the segmentation of brown fat, a PET-guided CT co-segmentation method is presented. With different variants of Convolutional Neural Networks (CNN), supervised learning strategies are proposed for the automatic diagnosis of lung nodules and IPMN. In order to address the unavailability of a large number of labeled examples required for training, unsupervised learning approaches for cancer diagnosis without explicit labeling are proposed. We evaluate our proposed approaches (both supervised and unsupervised) on two different tumor diagnosis challenges: lung and pancreas with 1018 CT and 171 MRI scans respectively. The proposed segmentation, quantification and diagnosis approaches explore the important adiposity-cancer association and help pave the way towards improved diagnostic decision making in routine clinical practice.

Effective water removal from ultra low sulfur diesel (ULSD) is considered an essential requirement to improve performance of diesel engine and achieve strict emission standards set for diesel engines by the Environmental Protection Agency (EPA). Due to relatively low interfacial tension between ULSD and water, water drops of fairly low sizes are observed in ULSD. If a conventional flow-through coalescence fiber filter is used, because of weak drop integrity, water drops may break very quickly and break as soon as they are formed which can result in minimal net gain in drop size and filter performance. The goal of this work is fabrication and testing of filter membranes made up of polymeric fibers. Superhydrophobic and hydrophilic polymeric fibers were prepared by the technique of electrospinning. Three different polymers poly (vinylidene fluoride hexafluoropropylene) (PVDF-HFP), polypropylene (PP) and poly (4-methyl-1-pentene) (PFMOP) were electrospun to produce superhydrophobic membranes. Tecophilic Polyurethane (TPU) was electrospun with WaterlockTM particles to produce hydrophilic fibers. Polymeric fibers were electrospun onto a glass fiber mat which acted as support to electrospun fibers. These membranes were characterized for their wettability using water contact angle and contact angle hysteresis. PVDF-HFP, PP and PFMOP membranes showed water contact angle greater than 150 degrees making them superhydrophobic and TPU, when electrospun with Waterlock particles made membranes hydrophilic in nature. Composite membranes were prepared by sandwiching hydrophilic fibers between glass fiber mat and superhydrophobic fibers. A coalescing filter in series with superhydrophobic fibers used and filtration performance was determined in all experiments.Experimental results showed all membranes performed very efficiently with separation efficiencies higher than 95%. The results and approach of this work will be useful in designing and developing filter media for separating water from ULSD.