Social capital and cyclones: how households' social networks contribute to disaster resilience and recovery in Bangladesh

Bangladesh is one of the most vulnerable countries in the world to cyclones and storm surges. Due to climate change, the frequency of cyclones and storm surges is expected to increase on the Bangladesh coast. These events create enormous damage and loss and increase community vulnerabilities. Over the last decade, many studies have examined how these vulnerabilities can be addressed and how the capacities of households can be strengthened to build more resilient communities. Little of this research has considered the contribution of social capital to disaster resilience and recovery in Bangladesh, and on the Indian sub-continent generally. This current research seeks to address this gap in the research by examining the contribution of social networks (particularly bonding networks - households' relationships with immediate family members and other relatives; bridging networks - households' relationships with neighbours and friends; and linking networks - households' relationships with organisations, for example NGOs, local government and other community-based organisations ) to disaster resilience and recovery. Through a mixed methods approach using household surveys, focus groups, key informant interviews, workshops and meetings, this study examines when social networks perform strongly and poorly in disaster resilience and recovery; how households' assets enable and constrain their contributions through bonding and bridging social networks; how social networks are articulated in the disaster management policies of Bangladesh; and what opportunities there are to strengthen the capacity of social networks to contribute effectively to disaster resilience and recovery, using two coastal villages affected by Cyclone Sidr as case studies. Findings show that bonding and bridging networks provide very important support - sharing of food and shelter, providing comfort, etc. - immediately after a disaster. As the time after the disaster increases, these networks perform less well due to households' limited physical, financial and human capital, and the uncertainties of their access to natural capital. After a period, bridging networks become less active and sometimes break down due to competition and conflict over access to external relief support. Bonding networks, however, do not break down. Household members continue contributing to the recovery process by reducing food intake, helping with alternative income and livelihood options through temporary migration and so on. For longer-term recovery, however, disaster victims usually need support through linking social networks - from NGOs (e.g. local, national and foreign NGOs), local government and other community-based organisations (CBO). their links with NGOs and local government provide households with strong support in the form of emergency relief, shelter, livelihood assistance, and reconstruction of major community services. However, while providing this support, they often engage in corruption through favouritism and taking bribes. These poor practices of NGOs and local government foster inequality, discontent and mistrust (between households, and between households and organisations), which, in the long run, harm linking relationships. This study found that despite the importance of social capital in disaster resilience and recovery, households' social networking relationships are not given adequate emphasis in the disaster management policies of Bangladesh ; and linking social networks are given greater focus than bonding and bridging networks. Within linking networks, government's links with various national, regional and international organisations and foreign states are prioritised, not households' links with local and national organisations. This study argues that NGOs and local government should strengthen the capacity of local households to contribute effectively to disaster resilience and recovery. This can be accomplished by placing more emphasis on disaster risk reduction programs rather than simply relief works, fostering alternative income options, providing more robust housing, and rebuilding trust through fair distribution of recovery support to build disaster-resilient communities. Through these measures, disaster-affected households would be able to reduce their dependency on the intervention of external organisations (linking social networks) to recover from a disaster. This study also suggests that disaster policies should be revised to make better use of the potential of local social capital to contribute to disaster resilience and recovery

Stochastic Programming Based Objective Function Optimization for Predictive Thrust Control of Linear Induction Machine

Model predictive thrust control (MPTC) is one of the most effective approaches for linear induction motor (LIM) drive system. It can achieve the optimization of multiple objectives. However, the process of tuning the weighting factors in the objective function is the main drawback of MPTC. It greatly increases the computation burden. In this paper, the tuning process of weighting factors is regarded as a random sampling process. Then, a novel weighting factor optimization method based on the stochastic programming technique is proposed to select the suitable control action for LIM. It will optimize with flux and thrust together to avoid the adjustment of weighting factor. In this paper, the optimal model can be solved by Monte Carlo simulation. At last, the simulation results have shown better dynamic and steady state performance of the proposed method

Optimal Design of a Multiwinding High-Frequency Transformer Using Reluctance Network Modeling and Particle Swarm Optimization Techniques for the Application of PV-Linked Grid-Connected Modular Multilevel Inverters

This article presents an optimal design procedure and development of a multiwinding high-frequency transformer for application in the cascaded modules of a grid-connected modular multilevel inverter. The transformer should be designed for a certain value of inductances and high efficiency because of its effect on the performance of the entire modular structure. To realize such an accurate design procedure with minimum computation effort and design complexity, a three-stage method including initial design using lumped-parameter modeling, optimal design using particle swarm optimization with reluctance network modeling and finite element method is proposed. An amorphous-based toroidal core transformer is designed, developed, and tested under different load conditions and frequency range to validate the design procedure

Was the post-1870 fertility transition a key contributor to growth in the West in the twentieth century?

Was the post-1870 fertility transition a key contributor to growth in the West in the twentieth century

Techno-economic analysis of the hybrid solar pv/h/fuel cell based supply scheme for green mobile communication

Hydrogen has received tremendous global attention as an energy carrier and an energy storage system. Hydrogen carrier introduces a power to hydrogen (P2H), and power to hydrogen to power (P2H2P) facility to store the excess energy in renewable energy storage systems, with the facts of large-scale storage capacity, transportability, and multiple utilities. This work examines the techno-economic feasibility of hybrid solar photovoltaic (PV)/hydrogen/fuel cell-powered cellular base stations for developing green mobile communication to decrease environmental degradation and mitigate fossil-fuel crises. Extensive simulation is carried out using a hybrid optimization model for electric rnewables (HOMER) optimization tool to evaluate the optimal size, energy production, total production cost, per unit energy production cost, and emission of carbon footprints subject to different relevant system parameters. In addition, the throughput, and energy efficiency performance of the wireless network is critically evaluated with the help of MATLAB-based Monte-Carlo simulations taking multipath fading, system bandwidth, transmission power, and inter-cell interference (ICI) into consideration. Results show that a more stable and reliable green solution for the telecommunications sector will be the macro cellular basis stations driven by the recommended hybrid supply system. The hybrid supply system has around 17% surplus electricity and 48.1 h backup capacity that increases the system reliability by maintaining a better quality of service (QoS). To end, the outcomes of the suggested system are compared with the other supply scheme and the previously published research work for justifying the validity of the proposed system

Modeling and Design of a Multiport Magnetic Bus-Based Novel Wind-Wave Hybrid Ocean Energy Technology

This paper proposes a multiport magnetic bus (MMB)-based novel wind-wave hybrid ocean energy technology (HOET). The ocean waves are mixed frequency waves and generate unique frequency spectra. The wave energy converters (WECs) connected to the linear permanent magnet generators generate voltages with varying amplitudes and frequencies due to the variation of the wind speed and direction. The proposed MMB of the proposed compact wind-wave HOET can provide galvanic isolation and allow a high-frequency operation of the MMB. A decoupled voltage and current control architecture is proposed to regulate the voltage and current waveforms in the high-frequency inverter modules of the MMB that can integrate multiple WECs. An Archimedes wave swing-based conversion method is utilized for the modeling and the design of the proposed WEC. A damping controller is designed to extract the maximum power from the irregular waves. For the wind-energy generation system, a doubly-fed induction generator-based technology is considered. The simulation and the laboratoryscale experimental results validate the potential and the applicability of the proposed wind-wave HOET as an effective means to harness ocean energy

Characterization of the High Graded Magnetic Material based Linear Generator for Wave Energy Conversion

Characterization of a permanent magnet linear generator (PMLG) for harvesting oceanic wave energy is presented in this paper. For the characterization, a PMLG has been designed which has a translator containing permanent magnet and vertically symmetric stator. Different high graded magnetic materials are applied to the PMLG to generate high amount of electrical power. As a part of characterization, load profile is analyzed to determine its peak generated power for each of the magnetic materials. Comparison of generated voltage, generated voltage, load current, output power, and magnetic flux linkage of the PMLG are presented in detail. Translator force and velocity are determined to calculate the efficiency of the PMLG. The analysis is performed with finite element method by using ANSYS/Maxwell software. Armature reaction, demagnetization, and core loss that occurs in the PMLG are considered for the analysis

Fault Analysis and Diagnosis for Induction Motor Based on Hilbert Transform and Support Vector Machine Classification Method

With the wide applications of the asynchronous induction motor (IM), various kinds of the electrical and the mechanical faults have been appearing, the main ones of which are the inter-turn short circuit of the stator, the broken-bar of the rotor and the air-gap eccentricity. This paper analyzes the current and the torque of the IM under fault conditions as well as providing fault components. Hilbert transform and the support vector machine (SVM) multi-classification method are applied to improve the sensitivity of fault identification and eliminate the interference of the environmental electromagnetic noise. In order to increase the diagnosis accuracy in different applications, the grid search (GS), the genetic algorithm (GA) and the particle swarm algorithm (PSA) are employed for the parameter optimization of the SVM classification prediction model. The simulation and the experimental results verify the proposed analysis and diagnosis method

The Novel Low Reluctance Superconducting Permanent Magnet Linear Generator for Oceanic Wave Energy Extraction

In this paper, the low reluctance superconducting direct drive linear generator (DDLG) for harvesting oceanic wave is presented. At first, a permanent magnet DDLG is designed in the ANSYS/Maxwell environment. The DDLG with both the copper and superconducting winding are characterized with finite element analysis. The DDLG is analyzed with the conventional and recently developed M5 Carlite magnetic cores. High graded neodymium iron boron permanent magnet, N46SH is selected for the DDLG to create strong magnetic field. It is analyzed that the proposed superconducting DDLG with M5 Carlite magnetic core and N46SH permanent magnet produces 294 kW more electrical power compared to that of the DDLG with copper conductor. It is also found that the stator size of the proposed DDLG is much smaller than the conventional one for designing the winding with superconducting tape

Electromagnetic design and vibration analysis of a homopolar linear synchronous motor

In this paper, the electromagnetic and mechanical characteristics of the improved homopolar linear synchronous motor (H-LSM) have been studied. Firstly, the influence of the ratio of the width and pitch of the rotor teeth is investigated on the magnetic field distribution and vibration traits. By establishing a simplified three-dimensional magnetic circuit model, the distribution of air gap flux density is attained. Secondly, the time and space distributions of the air gap flux density is decomposed, and the ratio of tooth width to tooth pitch with larger fundamental component is selected as the key index to design the H-LSM. Thirdly, through the modal analysis of the primary core, detailed investigation on the harmonics response is carried out, and the resonance frequency domain in the working process is clarified. Finally, 1-10th order frequency spectrum on the H-LSAM resonance is decomposed, which can provide a judgment for the fault diagnosis