Quantitative Assessment of Water Security Using a Hydrological Modeling Framework

Water scarcity and drought are major threats to water security. Quantifying and defining boundaries between these threats are necessary to properly assess water security of a region. A comprehensive assessment of water security in terms of water scarcity, water vulnerability and drought can address water policy issues related to hydrological conditions and their interactions with societal and ecosystem functioning. Therefore, study of water security can provide useful information to multiple stakeholders. The overarching goal of this thesis is to improve water security in river basins around the world. To demonstrate our proposed methods, we selected Savannah River Basin (SRB) as a case study. In addition to water security assessment of SRB, we also explored the combined as well as individual roles of climate, anthropogenic (e.g., urbanization, agriculture, water demand) and ecological elements on various aspects of water security. Realizing the importance of water security impacts on society and ecosystem, the following objectives are formulated: 1) To investigate the blue and green water security of Savannah River Basin by applying the water footprint concept. 2) To quantify the influence of climate variability and land use change on streamflow, ecosystem services, and water scarcity. 3) To assess the climate, catchment, and morphological variables control over hydrological drought of a river basin. To summarize, the results obtained from first objective shows that our proposed modeling framework can be applied to investigate spatio-temporal pattern of blue and green water footprints as well as water security at a county scale for SRB, thereby locating the emerging hot spots within the river basin. The results obtained from second objective indicate that the land use change and climate variability have a key influence (either concomitant or independent) in altering the blue (green) water and related water security over the basin. The results based on third objective demonstrate that in addition to climate variables, catchment and morphological properties significantly control short, medium and long-term duration of hydrological droughts in SRB. An integrated modeling framework was developed to achieve these objectives and additional findings are explained in detail through the following chapters

Molecular Engineering Approaches to Highly Structured Materials

Design and synthesis of novel supramolecular architectures is an interesting area of research in the last two decades. Intermolecular interactions assisted self-assembly of molecular and macromolecular building blocks play an important role in obtaining the desired shape and function of the supramolecular architectures. A combination of the classical covalent synthesis with the self-assembly assisted formation of well-defined architectures (noncovalent synthesis) allows us to develop novel multifunctional materials. Our approach in this area is focused on the design of novel molecular and biomolecular building blocks and the optimization of structure-property relationship of the materials using self-assembly approach. This presentation will focus on our recent efforts on the design and synthesis of polymers and oligopeptides for investigation of the self-assembly and fine-tuning the structure-property relationship. Also, some highlights will be given on our initial investigation on how hard minerals are synthesized by natural molecules through the self-assembly processes.Singapore-MIT Alliance (SMA

Molecular Engineering of Conjugated Polymers for Sensor Applications

In recent years, the application of fluorescent conjugated polymers for sensing chemical and biological analytes has received much attention from many researchers. A promising development in this direction was the fabrication of conducting polymer-based sensors for the detection of metal ions, small organic molecules and biomolecules. Herein, we have designed, synthesized and studied a series of copolymers containing alternate phenylene and 2,5- or 2,6-substituted pyridine rings. The basic N-atom of the pyridine ring and the adjacent –OH group from the phenyl ring provide binding sites for metal ions. Another series of water-soluble conjugated polymers with propoxy sulfonate side chains are investigated for biosensor applications. Significant quenching of the polymer fluorescence upon addition of viologen derivatives was also observed. The quenching effect on the polymer fluorescence confirmed that the newly synthesized polymers can be useful in the application of metal and biological sensors.Singapore-MIT Alliance (SMA

Molecular Engineering of Amphiphilic Pyridine Incorporated Conjugated Polymers for Metal Ion Sensors

Recent developments in the synthesis and structure-property investigation studies of conjugated polymers have led to the design of novel polymeric materials with tailored properties for advanced technological applications. A promising development in this direction involves the fabrication of conducting polymer based sensors for the detection of metal ions and small organic molecules. Herein, we designed, synthesized and studied a series of amphiphilic copolymers containing alternate phenylene and 2,5- or 2,6- or 3,5-substituted pyridine rings. The basic N-atom of the pyridine ring and the adjacent –OH group from the phenyl ring provide binding sites for metal ions. Thermal properties, and optical properties of polymers in presence of acid, base and metal ions are investigated. A few target polymers showed high sensitivities for metal ions in solution.Singapore-MIT Alliance (SMA

Synthesis, Optical properties and Applications of Water Soluble Conjugated PPPs for Biosensors

In recent years, application of fluorescent conjugated polymers to sense chemical and biological analytes has received much attention owing to its technological significance. Water soluble conjugated polymers are interesting towards the developing sensors for biomolecules. In this present contribution, we describe the syntheses and characterization of a series of water soluble conjugated polymers with sulfonic acid groups in the side chain. Such anionic conjugated polymers are designed to interact with biomolecules such as cytochrome-C. All polymers are water soluble and showed strong blue emission. Significant quenching of the fluorescence from our functionalized PPP was observed upon addition of viologen derivatives or cytochrome -C.Singapore-MIT Alliance (SMA

Towards co-sintering of oxide-based inorganic solid-state batteries. Understanding and overcoming thetemperature barriers.

220 p.All inorganic solid-state batteries (SSBs) are considered the batteries of the future because of their superior energy density and safety. Their commercialization is in its infancy since further understanding of the materials and processing aspects is still required. Here we propose an oxide-based SSB model comprising NMC+LATP+carbon composite cathode, LATP solid electrolyte, and Li metal anode able to potentially convey an energy density of >300 Wh/kg and >700 Wh/l. A review of existing processing techniques of the selected materials indicates the necessity of very high densification temperatures to assure sufficient ionic conductivity and mechanical stability. The electrode and electrolyte need to be co-densified to avoid interfacial contact resistance, but the components of the composite cathode react at these elevated temperatures. In this work, the composite cathode thermal compatibility is first studied to determine the tolerance of the system under temperature, considering also the heating atmosphere and the decomposition reaction mechanism. In a second step, mitigation strategies to overcome the threshold limits identified have been examined, such as the selection of the carbon conducting additive and the impact of other additives. On the other hand, the realization that the threshold temperature is much lower than the conventional processing temperature requires the exploration of alternative low-temperature densification techniques. Hence a high-pressure low-temperature (HPLT) technique has been identified and initially investigated for oxide-based ceramic solid electrolyte densification. Our results show that this technique enables a significant reduction of the processing temperature and time compared to conventional sintering. Finally, preliminary investigations indicate that with further exploration of the HPLT technique, the realization of the proposed SSB model should be possible, resulting in significant gains of processing consumed energy.energiGUN

Anti-proliferative activity of silver nanoparticles

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Eggshell Matrix Protein Mimetics: Elucidation of Molecular Mechanism of Goose Eggshell Calcification using Designed Peptides

Model peptides were designed, synthesized and conducted a detailed structure-property study to unravel the molecular mechanism of goose eggshell calcification. The peptides were designed based on the primary structural features of the eggshell matrix proteins ansocalcin and OC-17. In vitro CaCO₃ crystal growth experiments in presence of these peptides showed calcite crystal aggregation as observed in the case of the parent protein ansocalcin. The structure of these peptides in solution was established using intrinsic tryptophan fluorescence studies and quasi-elastic light scattering experiments. The structural features are correlated with observed results of the in vitro crystallization studies.Singapore-MIT Alliance (SMA

Designer peptides to understand the mineralization of calcium salts

Recently, we reported the extraction, purification and amino acid sequence of ansocalcin, the major goose eggshell matrix protein. In vitro studies showed that ansocalcin induces spherical calcite crystal aggregates. We designed two peptides using the unique features of the sequence of ansocalcin and the role of these peptides in CaCO₃ crystallization was investigated. The peptides showed similar activities as compared to ansocalcin, but at a higher concentration. The full characterization of the peptides and a rational for the observed morphology for the calcite crystals are discussed in detail.Singapore-MIT Alliance (SMA

Differential regulation of intracellular factors mediating cell cycle, DNA repair and inflammation following exposure to silver nanoparticles in human cells

10.1186/2041-9414-3-2Genome Integrity3