‘We knew a cyclone was imminent’:Hazard preparedness and disaster management efficiency nexus in coastal Bangladesh

"Natural hazard-prone countries in the global south adopted an anticipatory-preparedness approach in disaster risk reduction (DRR) by shifting away from the response and rehabilitation approach. It was highly associated with the policy recommendations of the United Nations Office for Disaster Risk Reduction (UNDRR) framework. Nevertheless, challenges remained in managing disaster risks due to heterogeneous efficiency among disaster managers. This research examines the institutional effectiveness of the disaster management agency in cyclone-prone areas in southwestern coastal Bangladesh through network analysis. This research also explores institutional efficiency’s impact on household preparedness in mitigating losses. We collected two distinct data sets from the local Union Disaster Management Committee (UDMC) and households in the same operational area of UDMC that were at risk of cyclonic disasters. To evaluate the effectiveness of local disaster management institutions, we conducted structured interviews with 336 representatives, spanning eight UDMCs in the cyclone-prone regions. To assess the impact of institutional performance (specifically, the UDMCs) on household disaster preparedness and loss mitigation, we collected data from 696 at-risk households. These households were located within the operational zones of the eight UDMCs, and the data was obtained using a structured questionnaire. Based on the application of social network analysis, our findings demonstrated that UDMC members were more active in the aftermath of disasters, as confirmed by three centrality measures - degree, eigenvector, and betweenness. Consequently, upon employing the Negative Binomial and Poisson regression models, we found a positive association between household engagement with UDMCs and participation in disaster preparedness training. This training appeared to enhance the knowledge and capacity of the respondents. The spill-over effects from disaster preparedness appeared to bolster the resilience of at-risk households, assist them in avoiding disaster-induced damages, and maintain consumption stability in the wake of disasters.

Development of nanocomposites for energy storage devices

With the ever-increasing need in improving the performance and operation life of future mobile devices, developing higher power density energy storage devices has been receiving more attention. Lithium ion battery (LIB) and capacitor are two of the most widely used energy storage devices and have attracted increasing interest from both industrial and academic fields. Batteries have higher power density than capacitor but significantly longer charge/discharge rates. In order to further improve the performance of these energy storage devices, one of the approaches is to use high specific surface area nano-materials. Among all the nano-materials developed so far, one-dimensional nanowires are of special interests because of their high surface-to-volume ratio and aligned pathway for electron diffusion and conduction. Therefore, in this thesis work, zinc oxide nanowires are implemented as an anode along with carbon fiber/graphene to increase the performance of LIB while lead titanate nanowires are used to improve the energy density of capacitors. For batteries, zinc oxide nanowires are grown on carbon cloth by low temperature hydrothermal method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to analyze morphology and crystal structures of samples. The performances of LIB using zinc oxide nanowire coated carbon cloth and bare carbon cloth are compared to show the improvement induced by zinc oxide nanowires. For capacitors, lead titanate (PTO) nanowires are used with Polyvinylidene fluoride (PVDF) to make nanocomposites of high dielectric constants. Lead titanate nanowires are synthesized by low temperature hydrothermal method. XRD and SEM are used to analyze as synthesized nanowires. Different volume fraction of PTO nanowires is used with PVDF to make dielectric for capacitor. Dielectric constant and breakdown voltage at variable frequency are determined to calculate energy density and specific energy density. The influence of temperature on energy densities of different volume fraction PTO nanocomposites is also determined in this thesis work