A Numerical Thermal Analysis of a Battery Pack in an Electric Motorbike Application

Today, electric driven motorbikes (e-motorbikes) are facing multiple safety, functionality and operating challenges, particularly in hot climatic conditions. One of them is the increasing demand for efficient battery cooling to avoid the potential thermal stability concerns due to extreme temperatures and the conventional plastic enclosure of the battery pack. A reliable and efficient thermal design can be formulated by accommodating the battery within an appropriate battery housing supported by a cooling configuration. The proposed design includes a battery pack housing made of high conductive materials, such as copper (Cu) and aluminum (Al), with an adequate liquid cooling system. This study first proposes a potted cooling structure for the e-motorbike battery and numerical studies are carried out for a 72 V, 42 Ah battery pack for different ambient temperatures, casing materials, discharge rates, coolant types, and coolant temperatures. Results reveal that up to 53 °C is achievable with only the Cu battery housing material. Further temperature reduction is possible with the help of a liquid cooling system, and in this case, with the use of coolant temperature of 20◦ C, the battery temperature can be maintained within 28 °C. The analysis also suggests that the proposed cooling system can keep a safe battery temperature up to a 5C rate. The design was also validated for different accelerated driving scenarios. The proposed conceptual design could be exploited in future e-motorbike battery cooling for optimum thermal stability

Planning exceptionalism? Political Economy of Climate Resilient Development in Bangladesh

As part of an international project led by Institute of Development Studies to understand change processes required for delivery of climate resilient and low carbon development this case study illustrates how a significant change process of a transnational problem depends on the interplay of actors, their ideas and power relations in a particular political circumstance influenced by international climate governance, initiatives, and actors. This shows the strength and weakness of Bangladesh‟s planning process especially in understanding whether existing power relations, interests and ideology of different actors can explain why some ideas win and some do not. The study findings are not only beneficial for Bangladeshi policy makers, researchers and public but also other climate vulnerable countries pursuing similar planning process.DfI

A numerical thermal analysis of a battery pack in an electric motorbike application

Today, electric driven motorbikes (e-motorbikes) are facing multiple safety, functionality and operating challenges, particularly in hot climatic conditions. One of them is the increasing demand for efficient battery cooling to avoid the potential thermal stability concerns due to extreme temperatures and the conventional plastic enclosure of the battery pack. A reliable and efficient thermal design can be formulated by accommodating the battery within an appropriate battery housing supported by a cooling configuration. The proposed design includes a battery pack housing made of high conductive materials, such as copper (Cu) and aluminum (Al), with an adequate liquid cooling system. This study first proposes a potted cooling structure for the e-motorbike battery and numerical studies are carried out for a 72 V, 42 Ah battery pack for different ambient temperatures, casing materials, discharge rates, coolant types, and coolant temperatures. Results reveal that up to 53 °C is achievable with only the Cu battery housing material. Further temperature reduction is possible with the help of a liquid cooling system, and in this case, with the use of coolant temperature of 20 °C, the battery temperature can be maintained within 28 °C. The analysis also suggests that the proposed cooling system can keep a safe battery temperature up to a 5C rate. The design was also validated for different accelerated driving scenarios. The proposed conceptual design could be exploited in future e-motorbike battery cooling for optimum thermal stability

Planning “Exceptionalism”? Political Economy of Climate Resilient Development in Bangladesh

Following three major disasters in 2007, Bangladesh intensified its effort to tackle climate change through development of the Bangladesh Climate Change Strategy and Action Plan (BCCSAP). The process of plan formulation led to debates nationally and internationally regarding the financing and integration of climate change into development planning. Using a political economic lens, this article illustrates how major national initiatives around international problems must be understood in terms of the interplay of actors, their ideas and power relations. The article argues that: (a) power relations among actors significantly influenced the selection of ideas and implementation activities; (b) donor concerns around aid effectiveness and consequent creation of parallel mechanisms of planning and implementation may run counter to both the mainstreaming process and the alignment of assistance with country priorities and systems; (c) climate change planning processes must be opened up to include actors from across sectors, population groups and geographical areas

A Diamond Shaped Multilevel Inverter With Dual Mode of Operation

This study presents a novel multilevel inverter structure that can operate in both switched capacitor and asymmetric DC source modes. In the first mode, it can produce seven-level output voltage employing two switched capacitors and one single DC supply. The five-level output voltage is produced while operating the second mode. The voltage ratio between the input and output voltage for the capacitor mode is 1:3 (triple voltage gain). During the first mode, the capacitor of the inverter is self -balanced whereas the inverter can produce higher voltage output in the DC source mode. The proposed inverter reduces the total standing voltage in both modes of operations as it can generate the output voltage without requiring any additional H-bridge circuit. The feasibility and predominate features of the proposed inverter have been established by comparing with existing topologies in terms of power components count. Results obtained from this study are validated using simulation employing sinusoidal pulse width modulation (SPWM). A hardware prototype has also been developed for further validation

The Political Economy of Climate Resilient Development Planning in Bangladesh

Following three major disasters in 2007, Bangladesh intensified its effort to tackle climate change through development of the Bangladesh Climate Change Strategy and Action Plan (BCCSAP). The process of plan formulation led to debates nationally and internationally regarding the financing and integration of climate change into development planning. Using a political economic lens, this article illustrates how major national initiatives around international problems must be understood in terms of the interplay of actors, their ideas and power relations. The article argues that: (i) Power relations among actors significantly influenced the selection of ideas and implementation activities; (ii) Donor concerns around aid effectiveness and consequent creation of parallel mechanisms of planning and implementation may run counter to both the mainstreaming process and the alignment of assistance with country priorities and systems; (iii) Climate change planning processes must be opened up to include actors from across sectors, population groups and geographical areas

Novel Insights into Integrin α11 Expression and Function

Integrins are a major group of cell surface receptors, which link the extracellular matrix with the cell cytoskeleton. They are heterodimeric proteins consisting of non- covalently bound α- and β-subunits. By regulating mechanotransduction at cell-ECM communication sites, integrins can also activate many intracellular signaling events, which are essential for cell proliferation, cell migration and gene regulation. Integrin α11β1 is a collagen-binding integrin, which expressed on subsets of fibroblasts. Recent data demonstrated that integrin α11b1 is involved in myofibroblast differentiation and in wound healing, but also is pro-tumorigenic in the tumor stroma and pro-fibrotic in fibrosis. However, detailed molecular insights underlying integrin α11β1 expression, distribution and function in the context of tissue reorganization remains to be determined. In this thesis, we used three different approaches to further characterize integrin α11 expression and function at both cellular and molecular level. Firstly, we investigated the functional role of integrin α11 cytoplasmic tail by deleting last 17 carboxyterminal amino acids in the α11 protein. We found that the cytoplasmic tail of α11 is important for collagen-dependent focal contact formation, collagen remodeling, cell proliferation and cell migration (Paper 1). Later, we generated and characterized a novel transgenic (ITGA11-Cre) mouse strain. Our results demonstrate that the activity of the 3 kb ITGA11 promoter driven Cre-recombinase in the ITGA11-Cre mouse is sufficient to replicate the endogenous expression of integrin a11 both during embryonic development and in fibrotic conditions including cardiac fibrosis and wound healing, respectively (Paper 2). Finally, we used newly developed monoclonal antibody (mAb) to human integrin a11 chain to demonstrate that α11 expression is present on different subset(s) of CAFs in the tumor microenvironment and a11b1 is involved in collagen remodeling and CAF migration in vitro (Paper 3). In summary, this thesis provides new understanding of integrin α11β1 functions in different subsets of fibroblasts in the context of tissue reorganization events including fibrosis and tumor-stroma interactions

Integrin α11 cytoplasmic tail is required for FAK activation to initiate 3D cell invasion and ERK-mediated cell proliferation

Integrin α11β1 is a collagen-binding integrin, which is receiving increasing attention in the context of wound healing and fibrosis. Although α11β1 integrin displays similar collagen specificity to α2β1 integrin, both integrins have distinct in vivo functions. In this context, the contribution of α11 subunit cytoplasmic tail interactions to diverse molecular signals and biological functions is largely unknown. In the current study, we have deleted the α11 cytoplasmic tail and studied the effect of this deletion on α11 integrin function. Compared to wild-type cells, C2C12 cells expressing tail-less α11 attached normally to collagen I, but formed fewer focal contacts. α11-tail-less cells furthermore displayed a reduced capacity to invade and reorganize a 3D collagen matrix and to proliferate. Analysis of cell signaling showed that FAK and ERK phosphorylation was reduced in cells expressing tail-less α11. Inhibition of ERK and FAK activation decreased α11-mediated cell proliferation, whereas α11-mediated cell invasion was FAK-dependent and occurred independently of ERK signaling. In summary, our data demonstrate that the integrin α11 cytoplasmic tail plays a central role in α11 integrin-specific functions, including FAK-dependent ERK activation to promote cell proliferation

Integrin α11 cytoplasmic tail is required for FAK activation to initiate 3D cell invasion and ERK-mediated cell proliferation

Integrin α11β1 is a collagen-binding integrin, which is receiving increasing attention in the context of wound healing and fibrosis. Although α11β1 integrin displays similar collagen specificity to α2β1 integrin, both integrins have distinct in vivo functions. In this context, the contribution of α11 subunit cytoplasmic tail interactions to diverse molecular signals and biological functions is largely unknown. In the current study, we have deleted the α11 cytoplasmic tail and studied the effect of this deletion on α11 integrin function. Compared to wild-type cells, C2C12 cells expressing tail-less α11 attached normally to collagen I, but formed fewer focal contacts. α11-tail-less cells furthermore displayed a reduced capacity to invade and reorganize a 3D collagen matrix and to proliferate. Analysis of cell signaling showed that FAK and ERK phosphorylation was reduced in cells expressing tail-less α11. Inhibition of ERK and FAK activation decreased α11-mediated cell proliferation, whereas α11-mediated cell invasion was FAK-dependent and occurred independently of ERK signaling. In summary, our data demonstrate that the integrin α11 cytoplasmic tail plays a central role in α11 integrin-specific functions, including FAK-dependent ERK activation to promote cell proliferation