Synthesis and Energy Applications of Mesoporous Titania Thin Films

The optical and electronic properties of TiO2 thin films provide tremendous opportunities in several applications including photocatalysis, photovoltaics and photoconductors for energy production. Despite many attractive features of TiO2, critical challenges include the innate inability of TiO2 to absorb visible light and the fast recombination of photoexcited charge carriers. In this study, mesoporous TiO2 thin films are modified by doping using hydrogen and nitrogen, and sensitization using graphene quantum dot sensitization. For all of these modifiers, well-ordered mesoporous titania films were synthesized by surfactant templated sol-gel process. Two methods: hydrazine and plasma treatments have been developed for nitrogen and hydrogen doping in the mesoporous titania films for band gap reduction, visible light absorption and enhancement of photocatalytic activity. The hydrazine treatment in mesoporous titania thin films suggests that hydrazine induced doping is a promising approach to enable synergistic incorporation of N and Ti3+ into the lattice of surfactant-templated TiO2 films and enhanced visible light photoactivity, but that the benefits are limited by gradual mesostructure deterioration. The plasma treated nitrogen doped mesoporous titania showed about 240 times higher photoactivity compared to undoped film in hydrogen production from photoelectrochemical water splitting under visible light illumination. Plasma treated hydrogen doped mesoporous titania thin films has also been developed for enhancement of visible light absorption. Hydrogen treatment has been shown to turn titania (normally bright white) black, indicating vastly improved visible light absorption. The cause of the color change and its effectiveness for photocatalysis remain open questions. For the first time, we showed that a significant amount of hydrogen is incorporated in hydrogen plasma treated mesoporous titania films by neutron reflectometry measurements. In addition to the intrinsic modification of titania by doping, graphene quantum dot sensitization in mesoporous titania film was also investigated for visible light photocatalysis. Graphene quantum dot sensitization and nitrogen doping of ordered mesoporous titania films showed synergistic effect in water splitting due to high surface area, band gap reduction, enhanced visible light absorption, and efficient charge separation and transport. This study suggests that plasma based doping and graphene quantum dot sensitization are promising strategies to reduce band gap and enhance visible light absorption of high surface area surfactant templated mesoporous titania films, leading to superior visible-light driven photoelectrochemical hydrogen production. The results demonstrate the importance of designing and manipulating the energy band alignment in composite nanomaterials for fundamentally improving visible light absorption, charge separation and transport, and thereby photoelectrochemical properties

A Study On Thermal Stability Of Palladiumcomposite Membrane Fabricated By Surfactant Induced Electroless Plating (Siep)

Thermal stability of the palladium membrane is a major challenge in hydrogen separation from mixture of gases at high temperature. To study the long term thermal stability of palladium membrane, thin, dense, and defect free Pd composite membranes on microporous stainless steel (MPSS) substrate were prepared by surfactant induced electroless plating (SIEP)

Dual Tobacco Use in a Random Sample of UK Resident Bangladeshi Men

PhDUK resident Bangladeshi men pose a public health challenge because of their preference for traditional tobacco use along side cigarette smoking. Studies investigating UK black and minority ethnic tobacco use have not had a primary focus on this issue. Furthermore, the extent and nature of dual tobacco use by Bangladeshi men had not been reliably established due to a reliance on self-report and a definitional confusion about paan with and without tobacco. This study aims to establish the prevalence of dual tobacco use by UK resident Bangladeshi men using a random survey design. It also plans to establish baseline information for dual tobacco use against the key determinants of a health inequality model. Psychosocial, health and nicotine related parameters of dual tobacco users are compared with cigarette only smokers and paan tobacco chewers. Risk factors for dual tobacco use have been explored through multivariate analysis. Three hundred and twenty-five men of Bangladeshi origin were randomly selected using the Tower Hamlets Electoral Register and interviewed at home using a pre piloted questionnaire incorporating items used in other relevant UK studies. Expired carbon monoxide readings were recorded using a Bedfont CO monitor. Dual tobacco was used by 22% of the sample, while 36% smoked cigarette only, 70/0 chewed paan tobacco only, and 350/0 did not use any form of tobacco. When dual tobacco users were compared with the cigarette smokers in bivariate analysis, there were significant differences in terms of self reported social class, age, education, employment, and heath status. A multivariate analysis controlling for age, education status, social class, self reported health and social capital scores showed tha1 only wife's tobacco use predicted dual tobacco use (OR=6.3). The findings from this study confirm the diversity and social nature of dual tobacco use by UK Bangladeshi men. These observations need to be considered and integrated into the development and implementation of tobacco cessation interventions for UK Bangladeshi adults in public health programs

Cumulative Impact of Shortest Path, Environment and Fuel Efficiency on Route Choice: Case Studies with Real-Time Data

Intelligent Transportation System (ITS) provides a great platform for the planners to reduce environmental externalities from auto. We now have access to real time data. We have been using shortest path to provide route choice to the user. But we have the potential to add more variables in choosing routes. Real time data can be used to measure carbon di-oxide emission during a trip. Also, fuel efficiency can be measured using the real time data. Planners should use this potential of ITS to reduce the environmental impact. This paper thus try to evaluate if considering three variables shortest path, environmental impact and fuel efficiency together instead of only shortest path will change the route choice or not. It provides case studies on different types of routes and between different sets of origin /destination to evaluate the combined influence of these three variables on route choice

A critical analysis of integrated coastal and ocean management in Bangladesh with lessons from global practices

The coast of Bangladesh is highly dynamic, unique and diverse, the south-western part of which hosts the world’s largest single mangrove forest; the south-central part receives the world’s second largest river system (Ganges-Brahmaputra-Meghna system), contributing to form the world’s largest delta in Bangladesh; and the south-eastern part provides room for major industrial and economic activities such as ports and shipping, ship recycling (2nd in global ranking), ship building, fisheries and tourism (Beaches in Cox’s Bazar – the world’s longest). The earlier land-side coastal management initiatives, which totally ignore ocean issues, have failed to bring a remarkable outcome mainly due to the lack of coordination, weak monitoring and evaluation mechanisms and knowledge gap. After the settlement of maritime boundary disputes with Myanmar (2012) and India (2014), Bangladesh gained a maritime area of 118,813 sq km (about 81% of the country’s land area), giving room to explore marine resources and expand ocean-based activities further towards the sea within national jurisdiction, for which the development of a comprehensive ocean governance framework and initiation of an MSP process is now being talked at the highest policy level. Given the country’s vulnerability to climate change and natural disasters that influence the lives and livelihood of the coastal community (28% of the country’s total population), development initiatives in the coastal area must consider adequate resilient and adaptive measures and conservation of marine resources for long-term sustainability. Informed decisions based on scientific and traditional knowledge, and past experience, can help the decision making process regarding coastal and ocean management become more sustainable

Market Efficiency, Time-Varying Volatility and Equity Returns in Bangladesh Stock Market

This paper empirically examines the issue of market efficiency and time- varying risk return relationship for Bangladesh, an emerging equity market in South Asia. The study utilizes a unique data set of daily stock prices and returns compiled by the authors which was not utilized in any previous study. The Dhaka Stock Exchange (DSE) equity returns show positive skewness, excess kurtosis and deviation from normality. The returns display significant serial correlation, implying stock market inefficiency. The results also show a significant relationship between conditional volatility and the stock returns, but the risk- return parameter is negative and statistically significant. While this result is not consistent with the portfolio theory, it is possible theoretically in emerging markets as investors may not demand higher risk premia if they are better able to bear risk at times of particular volatility (Glosten, Jagannathan and Runkle, 1993). While circuit breaker overall did not have any impact on stock volatility, the imposition of the lock-in period has contributed to the price discovery mechanism by reverting an overall negative risk-return time-varying relationship into a positive one. As a policy to improve the capital market efficiency, the timely disclosure and dissemination of information to the shareholders and investors on the performance of listed companies should be emphasized.

The Effect of Nitrogen Fertilization on Grain Protein Content and Yield of Spring Wheat in South Dakota

It has been predicted that the cost of nitrogen fertilizer will soon triple. Consequently, N management by wheat growers in South Dakota will be even more critical than it has been in the past. Nitrogen is one of the most limiting nutrients for wheat production in South Dakota. Many of the spring wheat producers fail to take advantage of nitrogen fertilizer recommendations based on soil testing. Therefore, it is likely that a simple post-harvest method of determining if adequate N was present for wheat crop would be very beneficial to spring wheat producers. One such method is using grain protein content as an indicator of N sufficiency or insufficiency. In 35 experiments that were conducted from 1963 through 1981, grain protein content was utilized to determine N response. This technique of using the grain protein content proved to be a useful indicator of yield response for spring wheat. Nine varieties were classified into three groups representing high, medium, and low grain protein content. These varieties were grown at three locations to determine their response to five levels of N fertilization. In general, all varieties produced similar yield and protein responses to varying N rates even though their general ranking for protein remained constant. The purpose of this study was three fold: (1) to determine the importance of variety selections on wheat yield and protein response to N; (2) to develop a model to predict the N required to maximize both yield and grain protein content and compare it with the existing model for nitrogen fertilizer recommendations; {3) to determine the relationship between relative grain yield and percent grain protein content