111 research outputs found
Data and Codes for Experimentally Validated Inverse design of Multi Property Fe-Co-Ni-alloys
No full text<p>Data and codes for the research work "Experimentally Validated Inverse design of Multi-Property Fe-Co-Ni alloys" authored by Shakti P. Padhy, Varun Chaudhary, Yee-Fun Lim, Ruiming Zhu, Muang Thway, Kedar Hippalgaonkar, & Raju V. Ramanujan.</p><p>Github link: https://github.com/Shakti-95/Data-and-Codes-for-Experimentally-Validated-Inverse-design-of-Multi-Property-Fe-Co-Ni-alloys</p>
The effect of crystallinity on photocatalytic performance of Co3O4 water-splitting cocatalysts
No full textCocatalysts, when loaded onto a water splitting photocatalyst, accelerate the gas evolution reaction and improve the efficiency of the photocatalyst. In this paper, we report that the efficiency of the photocatalyst is enhanced using an amorphous cobalt oxide cocatalyst. The WO3 film, when loaded with amorphous or nanocrystalline Co3O4, shows an improvement of up to 40% in photocurrent generation and 34% in hydrogen gas evolution. The effect of cocatalyst crystallinity on performance was systematically studied, and we found that the photocurrent deteriorates with the conversion of the cocatalyst to a highly crystalline phase at an annealing temperature of 500 degrees C. The mechanism of this effect was studied in detail using electrochemical impedance spectroscopy, and the enhancement effect produced by the amorphous cocatalyst is attributed to the large density of unsaturated catalytically active sites in the amorphous material
A highly active hydrogen evolution electrocatalyst based on a cobalt–nickel sulfide composite electrode
No full textA novel Co9S8–NixSy/Ni foam composite material was synthesized through the thermal decomposition of a cobalt–thiourea molecular precursor onto a 3D metallic support. The obtained electrode exhibited good activity toward the hydrogen evolution reaction in an alkaline medium, requiring a small overpotential of 163 mV at a current density of 10 mA cm?2, which is one of the lowest ever reported among transition metal sulfide materials
Novel materials and concepts for regulating infra-red radiation: radiative cooling and cool paint
No full textFacile Synthesis of Colloidal CuO Nanocrystals for Light-Harvesting Applications
No full textCuO is an earth-abundant, nontoxic, and low band-gap material; hence it is an attractive candidate for application in solar cells. In this paper, a synthesis of CuO nanocrystals by a facile alcohothermal route is reported. The nanocrystals are dispersible in a solvent mixture of methanol and chloroform, thus enabling the processing of CuO by solution. A bilayer solar cell comprising of CuO nanocrystals and phenyl-C61-butyric acid methyl ester (PCBM) achieved a power conversion efficiency of 0.04%, indicating the potential of this material for light-harvesting applications.This work was funded by the KAUST-Cornell Center for Energy and Sustainability. The authors thank Dr. Jacek Jasieniak (CSIRO, Australia) for inspiration for the copper oxide synthesis and helpful comments on the paper, William Baumgardner and John Grazul for assistance with TEM imaging, and Dr. Maura Weathers for assistance with XRD. Device fabrication and testing was performed partly in the laboratory of Professor George Malliaras, while nanocrystal characterization was done using equipment in the Cornell Center for Materials Research (CCMR), Cornell Center for Nanoscale Systems (CNS), Cornell Nanoscale Science & Technology Facility (CNF), and the KAUST-Cornell Center for Energy and Sustainability. Y. F. Lim acknowledges a research fellowship from A*STAR, Singapore. J. J. Choi acknowledges support from NSF IGERT fellowship
A community-based e-learning platform with a gamified environment for lifelong learners
No full textLifelong learning is a voluntary and self-motivated process of gaining knowledge and
developing new skills throughout your life. It is important to ensure competitiveness in
the continuously evolving world with industries expanding at a rapid rate. However, lack
of motivation and peer-support are potential pitfalls of online learning. This results in
lower completion rate of courses.
This projects aims to build an online learning website with gamification and study buddy
features to allow learners to have a fun and enjoyable time learning, and increasing the
completion rate of courses at the same time.
To achieve this objective, this project covers both the frontend and backend applications.
The frontend application is built using NextJs, a modern framework for production and
the backend application is built using Spring Framework with a microservice architecture.Bachelor of Engineering (Electrical and Electronic Engineering
Language use and language behaviour of Hong Kong Chinese students in Toronto
No full textgrantor:
University of TorontoThis study examines the relationship between language use and behaviour and their broader sociolinguistic and sociocultural environment. It explores first language use and behaviour of Hong Kong Chinese students in relation to the ethnolinguistic vitality of the Chinese community in Toronto. The thesis presents a bilingual, bicultural Chinese Canadian's view of linguistic changes and the effects on one of the largest linguistic minority groups in Toronto; it relates students' linguistic experiences to individual and social-environmental factors that affect the relationship between a minority and a majority group in a culturally diverse setting. The study seeks to identify the relevant sociological, socio-psychological and psychological variables that facilitate students' first language use and behaviour. It looks at whether students' positive or negative perceptions of the ethnolinguistic vitality of their ethnic group, their socio-psychological attitudes about the role and value of their language and culture, and their subjective ethnolinguistic vitality beliefs, are related to the variables. A total of 115 Chinese students mostly of Hong Kong origin; median age 13 years; 64% females; from two heritage language schools in different locations in Toronto, completed a questionnaire. In-depth follow-up interviews were conducted with 12 students who volunteered. Two theoretical models of ethnolinguistic vitality were applied to the Chinese situation in Toronto, linking sociostructural variables with students' subjective perceptions and ethnolinguistic identity and beliefs. The study investigated the role and extent of the first language (Cantonese) in students' daily life, and found evidence that there were plentiful opportunities for first language use, close linguistic and cultural contact with Chinese speakers, strong contact with the Chinese media, high motivation to learn and use the first language, positive attitude towards heritage language and cultural maintenance and high ethnolinguistic vitality of the Chinese group. Since a myriad of factors are associated with minority students' first language use and behaviour in a multilingual and multicultural environment, it was shown that Chinese students' positive attitude towards factors at the sociological, socio-psychological and psychological levels all help to facilitate students' first-language use and behaviour. Not only was the community vitality of the Chinese group in Toronto found to be high, but students' individual perception of that vitality was also high, fostering high first language vitality. A majority of the students also showed a balanced bicultural identity, and viewed themselves as equally Chinese and Canadian. Given strong first language use and behaviour, favourable conditions for heritage language and cultural maintenance, and the growing economic and political influence of the large Chinese minority group, issues are raised about how this group fits into the pluralist Canadian mosaic, and what present intergroup relations mean for multiculturalism in Canada. Considering the relationship between a minority and majority group of different and changing societal power relations, the author highlights implications for both the Chinese as well as the larger Canadian community.Ph.D
Language use and language behaviour of Hong Kong Chinese students in Toronto
No full textgrantor:
University of TorontoThis study examines the relationship between language use and behaviour and their broader sociolinguistic and sociocultural environment. It explores first language use and behaviour of Hong Kong Chinese students in relation to the ethnolinguistic vitality of the Chinese community in Toronto. The thesis presents a bilingual, bicultural Chinese Canadian's view of linguistic changes and the effects on one of the largest linguistic minority groups in Toronto; it relates students' linguistic experiences to individual and social-environmental factors that affect the relationship between a minority and a majority group in a culturally diverse setting. The study seeks to identify the relevant sociological, socio-psychological and psychological variables that facilitate students' first language use and behaviour. It looks at whether students' positive or negative perceptions of the ethnolinguistic vitality of their ethnic group, their socio-psychological attitudes about the role and value of their language and culture, and their subjective ethnolinguistic vitality beliefs, are related to the variables. A total of 115 Chinese students mostly of Hong Kong origin; median age 13 years; 64% females; from two heritage language schools in different locations in Toronto, completed a questionnaire. In-depth follow-up interviews were conducted with 12 students who volunteered. Two theoretical models of ethnolinguistic vitality were applied to the Chinese situation in Toronto, linking sociostructural variables with students' subjective perceptions and ethnolinguistic identity and beliefs. The study investigated the role and extent of the first language (Cantonese) in students' daily life, and found evidence that there were plentiful opportunities for first language use, close linguistic and cultural contact with Chinese speakers, strong contact with the Chinese media, high motivation to learn and use the first language, positive attitude towards heritage language and cultural maintenance and high ethnolinguistic vitality of the Chinese group. Since a myriad of factors are associated with minority students' first language use and behaviour in a multilingual and multicultural environment, it was shown that Chinese students' positive attitude towards factors at the sociological, socio-psychological and psychological levels all help to facilitate students' first-language use and behaviour. Not only was the community vitality of the Chinese group in Toronto found to be high, but students' individual perception of that vitality was also high, fostering high first language vitality. A majority of the students also showed a balanced bicultural identity, and viewed themselves as equally Chinese and Canadian. Given strong first language use and behaviour, favourable conditions for heritage language and cultural maintenance, and the growing economic and political influence of the large Chinese minority group, issues are raised about how this group fits into the pluralist Canadian mosaic, and what present intergroup relations mean for multiculturalism in Canada. Considering the relationship between a minority and majority group of different and changing societal power relations, the author highlights implications for both the Chinese as well as the larger Canadian community.Ph.D
Facile Synthesis of Colloidal CuO Nanocrystals for Light-Harvesting Applications
No full textCuO is an earth-abundant, nontoxic, and low band-gap material; hence it is an attractive candidate for application in solar cells. In this paper, a synthesis of CuO nanocrystals by a facile alcohothermal route is reported. The nanocrystals are dispersible in a solvent mixture of methanol and chloroform, thus enabling the processing of CuO by solution. A bilayer solar cell comprising of CuO nanocrystals and phenyl-C61-butyric acid methyl ester (PCBM) achieved a power conversion efficiency of 0.04%, indicating the potential of this material for light-harvesting applications.</jats:p
Photocatalytic and photoelectrochemical systems for oxidation of aromatic compounds in an aqueous environment
No full textAs the demand for chemical products increases, alongside a rising problem of pollution due to chemical wastes, there is great interest in developing systems that can resolve either or both issues in a sustainable way. Inspired by nature, the development of photocatalytic and photoelectrochemical (PEC) systems had been pursued as a possible solution. In this work, both a PEC system involving nanoporous bismuth vanadate (BiVO4) with tetraamidomacrocyclic ligand iron complexes (Fe-TAML) as co-catalysts and a photocatalytic system involving modified graphitic carbon nitrides (g-C3N4) were investigated. Both systems were also applied to the oxidation of bisphenol compounds, as well as the oxidation of lignin in lignocellulose. In addition, a hydrophobic metal halide perovskite photocatalytic system was explored for C-C bond cleavage and dehydrogenation reactions, while tetraamidomacrocyclic ligand cobalt complexes (Co-TAML) were investigated for hydrogen evolution reaction.
In Chapter 2, I present a literature review of the components of the photosystems we had worked on. These include reviews of lignocellulose and bisphenols as the substrates of interest, as well as the materials BiVO4, g-C3N4, and metal halide perovskites as viable semiconductors. The possible modifications and applications of the materials in various reactions were also investigated in this chapter. In addition, this chapter will also offer a look into the Fe-TAML co-catalysts and other TAML complexes, their origins and applications, before ending with a summary about how the proposed systems would be like.
Chapter 3 follows on by describing the syntheses and characterisations of the nanoporous BiVO4 plates and the addition of Fe-TAML as co-catalysts (from hereon known as BiVO4/Fe-TAML). The PEC activities of the resulting system were shown to be promising in oxidising a selection of substrates, namely bisphenol F (BPF), bisphenol S (BPS), and lignin.
Chapter 4 then describes a photocatalytic system involving a modified g-C3N4 that has both an improved surface area, as well as pyromellitic diimide (PDI) incorporated within the g-C3N4. The improvement to the photocatalytic ability of the resulting g-C3N4 was then discussed and examined, with subsequent application to the degradation of BPF.
Chapter 5 summarises the collaborative projects done in exploring metal halide perovskites as a photocatalysts and Co-TAML as an electrocatalyst, with further discussions into some characterisations of the materials and catalysts involved. The thesis concludes with Chapter 6 looking into possible future work.Doctor of Philosoph
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