Designing Nanocomposite Materials For Catalyzing Electrochemical Reactions in Anion Exchange Membrane Fuel Cells

Fuel cells are considered to be one the most promising sustainable energy technologies for energy conversion and electric power generation. With the development of stable, conductive and high performance anion exchange membranes and ionomers, there has been an increased interest towards studying various electrochemical reactions in Anion Exchange Membrane Fuel Cells (AEMFC). This increased attention has been attributed to the comparatively facile reaction kinetics, minimized corrosion effects and reduced fuel crossover in alkaline media. However, the oxygen reduction reactions (ORR) taking place in the cathode compartment of fuel cells plays a crucial role in optimizing the electrochemical energy conversion efficiency, which is why it’s imperative to design electrocatalysts that can efficiently catalyze the electroreduction of oxygen in alkaline media. Various studies have demonstrated the improved intrinsic activity, stability and accessibility of Palladium/Graphene-based nanocomposites for ORR in alkaline electrolytes, although their integration into operating AEMFCs have been quite limited to date. This is mainly due to the challenges associated with (i) synthesizing Pd nanoparticles without surfactants and organic stabilizers (ii) fabricating porous graphitized supports with controlled morphologies that can form triple phase boundaries and (iii) a lack of standardization and optimization for integrating these nanocomposite materials into the membrane electrode assemblies of AEMFCs. This work addresses the current limitations and technical challenges by providing a synthetic strategy for designing Pd/Graphene nanocomposites with i) controlled surface to volume ratios for enhancing the solid-liquid-gas phase boundaries, ii) modified chemical properties for improving nanoparticle dispersion and electrochemical accessibility and iii) targeted tuning of active sites through nitrogen functionalization for oxygen electroreduction in alkaline media. In particular, stable size-controlled Pd nanoparticles were synthesized using surfactant free technique and deposited on hierarchically structured nitrogen doped 3D-Graphene nanosheets that were fabricated with varying levels of micro-, and macro-porosities developed using a sacrificial templating and pyrolytic methods. Using a synergetic combination of potentiodynamic, surface analysis and spectroscopic techniques, it was demonstrated that the porosity, surface functionalization, and the nature of nitrogen moieties doped into played a significant role in in modifying the size, dispersion, electrochemical accessibility as well as activity of the Pd nanoparticles for oxygen electroreduction in alkaline media. The Pd/3D-Graphene composite materials were also integrated into a catalyst coated membrane, optimized (assembly, activation, electrode fabrication) and analyzed for their performance in H2/O2 fed AEMFCs operating at 60°C. It was demonstrated that conditioning of the membranes was crucial for reducing ohmic losses, whereas porosity of the supports was imperative for facilitating mass transport kinetics. Overall, this work analyzes how the morphological and chemical properties of graphitized supports can be modified to play a key role in improving oxygen electroreduction pathways not only in the alkaline electrolytes, but also in minimizing concentration polarization losses in operating AEMFCs. The results in this study further highlights the importance of rationally designing nanomaterials for high-performance energy conversion devices, and can also be expanded to other energy storage and conversion applications such as electrodes for Li-air batteries and electrolyzers

EXPLORATION OF TM-NX ORR ELECTROCATALYSTS FROM FIRST PRINCIPLE CALCULATIONS

Fuel Cells are promising candidates for the energy conversion technologies in particular for non-stationary applications. However, current fuel cells rely on rare and expensive Platinum catalysts and the power generation is limited by the sluggish oxygen reduction reaction (ORR) at the cathode. An interesting alternative material set which continues to attract significant attention are TM-Nx (TM = Fe, Co, x = 2 - 4) based non-PGM electrocatalysts where the defect motifs are embedded in a carbon matrix during pyrolysis. By studying the material properties of individual defects we can determine how the chemistry and morphology of these TM-Nx motifs are interdependent. Additional focus will also be on XPS characterization for the identification of the nature of proposed catalytic site(s). Although XPS is a widely used experimental technique for this purpose, the unique identification of structural motifs from XPS observations alone remains challenging. vi First-principles computations can provide us with the missing link by predicting core-level shifts for candidate defect motifs. This ability enables us to establish structure/property relationships directly and provides us with information that is critical for the detailed interpretation of XPS spectra. The incentive of this research thesis resides in the understanding of the electrochemical performance and energetics of these TM-Nx catalysts and the quest for the design of suitable catalysts with improved performance

Optical Character Recognition based on Template Matching

This paper presents an innovative design for Optical Character Recognition (OCR) from text images by using the Template Matching method.OCR is an important research area and one of the most successful applications of technology in the field of pattern recognition and artificial intelligence.OCR provides full alphanumeric visualization of printed and handwritten characters by scanning text images and converts it into a corresponding editable text document. The main objective of this system prototype is to develop a prototype for the OCR system and to implement The Template Matching algorithm for provoking the system prototype. In this paper, we took alphabet (A-Z and a-z), and numbers (0-1), grayscale images, bitmap image format were used and recognized the alphabet and numbers by comparing between two images. Besides, we checked accuracy for different fonts of alphabet and numbers. Here we used Matlab R2018a software for the proper implementation of the system

SARS-CoV-2 infection and diabetes: Pathophysiological mechanism of multi-system organ failure

Since the discovery of the coronavirus disease 2019 outbreak, a vast majority of studies have been carried out that confirmed the worst outcome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in people with preexisting health conditions, including diabetes, obesity, hypertension, cancer, and cardiovascular diseases. Likewise, diabetes itself is one of the leading causes of global public health concerns that impose a heavy global burden on public health as well as socio-economic development. Both diabetes and SARS-CoV-2 infection have their independent ability to induce the pathogenesis and severity of multi-system organ failure, while the co-existence of these two culprits can accelerate the rate of disease progression and magnify the severity of the disease. However, the exact pathophysiology of multi-system organ failure in diabetic patients after SARS-CoV-2 infection is still obscure. This review summarized the organ-specific possible molecular mechanisms of SARS-CoV-2 and diabetes-induced pathophysiology of several diseases of multiple organs, including the lungs, heart, kidneys, brain, eyes, gastrointestinal system, and bones, and sub-sequent manifestation of multi-system organ failure

A COMPARATIVE STUDY OF THE EDUCATIONAL SYSTEMS OF BANGLADESH AND FINLAND

This thesis compares the educational system of Bangladesh, a democratic South Asian country, with the educational system of Finland, a Scandinavian country that scores high in international comparisons on tests, such as PISA (Program for International Student Achievement). Areas for comparison include multilingualism, high stakes testing, teacher autonomy and motivation, urban/rural populations, special education, and teacher professionalism. The extent to which “the Finnish way” can help and direct improvements for the Bangladesh educational system is the major focus of the discussion. Drawing from Finnish education, the most attractive resolutions can be setting intervention for children with learning difficulties within the school system; empowering children’s native language; de-emphasizings testing; providing equal access to and resources for education in rural areas; increasing teachers’ autonomy, improving teachers’ working conditions; and ensuring teachers’ professional development

The influence of winter weather on high-crash days in Southern Ontario

Traffic crashes tend to occur at relatively greater frequencies at particular locations, at particular time periods, and for particular subsets of drivers and vehicles. It is well recognized among the road safety community that crash-risk is highly elevated when inclement weather conditions occur in the winter. To present, most of the road safety studies focus on event-based analysis or seasonal analysis and give little attention to explore high-risk conditions at the daily temporal scale. The purpose of the study is to advance our understanding of high-risk crash conditions at the daily level and their occurrences in Southern Ontario, Canada. The study explores different definitions of high-crash days, and quantifies the influences of weather conditions, risk exposure, months and timing of precipitation on the likelihood of a high-crash day occurring using binary logistic regression model. Additionally, an approach for estimating the relative risk exposure using available traffic count data has also been developed. The results of the study show a small proportion of high-crash days are responsible for a considerable amount of traffic crashes during the winter. The risk of traffic crash is twice as high on high-crash days in comparison to non-high-crash days. The modeling approach well-fits the data and shows that winter weather conditions have significant influence on high-crash days with results being mostly consistent across the four study areas, Toronto, the Area Surrounding Toronto, London and the Area Surrounding London. Low temperature, heavy snowfalls, high wind speeds, high traffic volumes, early winter months, occurrence of precipitation in both morning and evening increase the odds of high-crash days to a large extent. The results of study could help to pre-schedule traffic operation and enforcement, to effectively distribute road safety resources and personnel, and to create situational awareness among road users and other stakeholders

Monsoon Tourism: A New Aspiration for Bangladesh Tourism Industry

From the very past Bangalees are highly attached with the monsoon season and much influenced by the beauty of the rainy season. So we find a touch of the season in our every occasion and festivals. Most of the countries of the world are deprived from the blessings and beauty of the monsoon climate. So, every year lots of tourists from different countries (like Norway, Germany, Switzerland, Russia) come to visit different countries which are blessed by monsoon climate. They also come to visit Bangladesh. Like other seasons the rainy season of Bangladesh is also very suitable for the interested visitors. So, in this article we have tried to conduct a descriptive research to represent the current scenario with the emphasis on future impact of Monsoon tourism for the development of Bangladeshi tourism sector. Our research is based on both qualitative and quantitative data which we have collected from various sources like websites, articles, journals, etc.  Throughout our study we mainly try to focus on the future of Bangladesh tourism sector by introducing new phenomena monsoon tourism. Keywords: monsoon, tourism, tourist, Bangladesh, Bay of Bengal, Cox’s Bazar, rainy season

Monetary Policy Transmission Mechanism, Financial Frictions in closed and open economy DSGE models

The broad objective of the thesis is to analyze the monetary policy transmission and relative importance of various shocks in business cycles after considering the financial sector structure for both developing and developed countries in three self-contained chapters (Chapter 2-4). The thesis contributes both theoretically and empirically to the literature relating to monetary policy, financial frictions and competition structure, exchange rate pass through and open economy in general, using Structural Vector Auto-Regression (SVAR) and Dynamic Stochastic General Equilibrium (DSGE) models. Since the global financial crisis, a growing awareness of the roles of financial frictions has led to renewed interests in transmission mechanisms of monetary policy and other shocks. Two different financial frictions are incorporated in the DSGE models of Chapter 3-4 while Chapter 2 does not explicitly model financial friction and uses SVAR model to analyze the research questions. The effectiveness of monetary policy and its economy wide transmission mechanism are relatively unexplored in Bangladesh where financial sector is still developing. Hence, in Chapter 2, I investigate the effectiveness of monetary policy and its transmission mechanism with special emphasis on the lending channel. A SVAR model for Bangladesh is constructed, taking into account the exchange rate and monetary policy regimes in the identification scheme. The estimated model finds support for empirical regularities and existence of the bank lending channel. However, exchange rate channel appears less effective, reflecting a high degree of market intervention by the Bangladesh Bank. Frictions complicate the role of the financial sector particularly in the advanced financial markets. Therefore, in Chapter 3, I analyze the transmission mechanism of investment specific technology (IST) shock in presence of frictions between depositors and bankers (a la Gertler and Karadi, 2009) and implications of considering the capital quality and the net worth shocks as financial shocks. I use a DSGE framework in Chapter 3 as it allows to design and experiment shocks and frictions explicitly. The estimated model with a closed economy representation for the US shows that, financial friction weakens the impacts of IST shocks in business cycles. Also, the financial sector is important not only as amplifier of shocks originating in the real sector, but also as an independent source of shocks affecting the real economy substantially. Financial sector in many countries are not as competitive as in the US. Therefore, the financial friction discussed in Chapter 3 may not be relevant in those countries. Highly concentrated structure of the financial sector itself creates frictions affecting bank credits in important ways. Thus, in Chapter 4, I construct an open economy DSGE model with an oligopolistically competitive banking sector, considering Australia as an example. Oligopolistic competition is measured through interest markup which depends on the number of competing banks. The number of competitors is determined endogenously. The estimated model for Australia finds a strong stock market effect in presence of oligopolistic banks after a monetary policy shock making the shock less effective and such banks may amplify external shocks. Also, these banks appear to be more resilient to financial shocks indicating healthy bank balance sheet positions. The big picture projected by the dissertation is, the depth and complexity of the financial sector affect the way intermediaries contribute to cyclical fluctuations when shocks including monetary policy hit the economy. For example, IST shock's impacts on output are weakened by the financial frictions through a bank balance sheet effect when intermediaries are highly competitive. However, under oligopolistic bank competition, the IST shock may not trigger effective enough balance sheet effects due to strategic behavior among the banks, leaving a large role for the shock to play. Policy implications of the thesis along with a discussion on future research directions are summarized in Chapter 5

Archaeological and Historical Tourism: An Emerging Dimension for the Tourism Industry of Bangladesh

Bangladesh emerges as a popular tourist destination for her natural heritage, beautiful coasts and beaches, archeological remains, historical and religious places, hills and islands, forests and jungles and attractive countryside with inestimable water bodies and green fields of agriculture. These valuable natural and cultural heritages are major parts of our tourism industry. Every year, many nature loving people visit here and contribute a major part in our national economy. So, Bangladesh has many things to offer to our precious visitors, but Archaeological and historical tourism in Bangladesh, as a fragment of the larger tourism industry, can be the major contributor to total tourism earnings. “Foreign tourists who come to Bangladesh, like to enjoy archaeological and historical places first, while their second choice is scenic beauty” (Ali & Parvin, 2010). Keywords: Archaeology, Bangladesh, History and Tourism

A study on the listening and speaking skills in English at HSC level : challenges and possible solutions

This thesis is submitted in partial fulfillment of the requirements for the degree of Bachelor of Arts in English, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (page 44-46).In the field of English language teaching in Bangladesh, it is generally seen that only two of the four skills of the language-reading and writing are taught. But a course on English language is any level of education needs to focus on the four skills of the language, listening, speaking, reading and writing. As a result, the other two skills, listening and speaking, are neglected in the teaching of English in Bangladesh. Consequently the proficiency of learners in these two skills of the English language relatively poor. This study explores the strategies the learners at the Intermediate level employ in learning the speaking and listening skills in English. At the same time this study explores the situations of teaching these two skills in English at HSC level in Bangladesh. In order to investigate the above mentioned issues an interview was conducted. The interview comprised of eight respondents from eight different colleges of Dhaka, Bangladesh. Data was collected using a questionnaire on language learning strategies of the HSC level learners in Bangladesh. The finding shows the some challenges and possible solutions on the way of applying these two skills at HSC level students.Sadia AfrinB.A. in Englis