Doctor of Philosophy

dissertationThis study is focused on fabrication and characterization of Cu2ZnSnS4 (CZTS) films on transparent conducting substrate. CZTS films were synthesized using solution based methods. A specially designed sequential and single stage electrochemical method as well as spin coating method was used to grow layers of precursors. Deposition of constituent metallic layers was carried out on SnO2/F (Fluorinated tin oxide or FTO) coated glass substrates. The electrodeposited/spin coated layers were annealed in a sulfur environment to obtain CZTS. Structural, morphological and optical characterization experiments were performed using several techniques including x-ray diffraction, Raman and UV-visible spectroscopy, scanning electron microscopy, and atomic force microscopy. All characterization experiments indicated the films are single phase with a measured direct band gap of ~1.5 eV. Photocurrent response of CZTS film grown on FTO substrate was measured using alternating front illumination and rear illumination in a Eu3+/Eu2+ solution environment. The photoelectrochemical response exhibited during rear illumination is comparable to that obtained for front illumination. The promising photocurrent data for CZTS films suggest these films have potential application in a variety of photovoltaic devices. A comparative study revealed that photoelectrochemical response exhibited by the films grown on molybdenum substrate is greater than that obtained for film grown on FTO substrate. A modified form of the Gartner model to explain J-V characteristics for CZTS-electrolyte solution has been proposed. Fundamental information such as energy band gap-temperature relationship and temperature dependent study of Raman ‘A' mode for CZTS thin films were also investigated in this research

Water and sanitation hygiene practices among household members living in urban slum in Gwalior city: a cross sectional study

Background: Population inhabit in urban slum of developing countries face sanitation, water supply and cleanliness related issues. We contemplated knowledge, attitudes and practices identified with drinking water and sanitation offices among urban slum populace of Gwalior city, Madhya Pradesh, India.Methods: It was a cross-sectional study comprising of individuals over 18 years of age residing at Muriya Pahar and Awadpura, Urban Slum, Gwalior (Madhya Pradesh) from September 2019 to December 2019. Total 120 individuals were interviewed using simple random sampling technique. Basic information about socio-demographic profile and existing drinking water and sanitation related knowledge, attitude, and practices was collected using a modified version of previously validated questionnaire and analysed.Results: Thirty five percent (35%) of the participants were following bleach/chlorine methods of water treatment while twenty five percent (25%) of the participants felt that water available to them was clean and did not require any additional treatment. Forty percent (40%) of the participants surveyed, did not have access to toilets inside their households.Conclusions: There is a requirement for mediation to instruct people about drinking water treatment techniques, sanitation, and hand washing rehearses

The Design and Regulation of Exchanges: A Formal Approach

We use formal methods to specify, design, and monitor continuous double auctions, which are widely used to match buyers and sellers at exchanges of foreign currencies, stocks, and commodities. We identify three natural properties of such auctions and formally prove that these properties completely determine the input-output relationship. We then formally verify that a natural algorithm satisfies these properties. All definitions, theorems, and proofs are formalized in an interactive theorem prover. We extract a verified program of our algorithm to build an automated checker that is guaranteed to detect errors in the trade logs of exchanges if they generate transactions that violate any of the natural properties

Heat Transfer and Pressure Drop Investigation in a Circular Tube by the use of Various Kinds of Inserts

160–163The ability of a traditional heat exchanger in transferring heat requires improvement for conveying a considerable proportion of energy at cheaper rate and amount. For augmenting the heat transfer coefficient, different means have been employed. However, the use of inserts has become an assured method in enhancing heat transfer through endurable escalation of frictional losses. The grinding factor improvement proportions are observed to be in the scope of 2.68-3.43, 3.14-4.14, 4.30-5.34, 5.22-6.18 and 6.53-6.96 for the previously mentioned configurations of additions.The objective of the investigation is the examination of a circular tube fitted with multiple inserts with regard to its characteristics related to fluid flow & heat transfer; these inserts are organized in co-swirl and counter-swirl directions

Verified Double Sided Auctions for Financial Markets

Double sided auctions are widely used in financial markets to match demand and supply. Prior works on double sided auctions have focused primarily on single quantity trade requests. We extend various notions of double sided auctions to incorporate multiple quantity trade requests and provide fully formalized matching algorithms for double sided auctions with their correctness proofs. We establish new uniqueness theorems that enable automatic detection of violations in an exchange program by comparing its output with that of a verified program. All proofs are formalized in the Coq proof assistant without adding any axiom to the system. We extract verified OCaml and Haskell programs that can be used by the exchanges and the regulators of the financial markets. We demonstrate the practical applicability of our work by running the verified program on real market data from an exchange to automatically check for violations in the exchange algorithm

What is Your Selfie Worth? A Field Study on Individuals’ Valuation of Personal Data

Referred to as the new oil, undoubtedly personal data is a valuable resource for organizations. Contrary, it is still blurred, to what extent individuals value their data even though, in a digitized world, users are requested to exchange their data for adequate services. Former research on individuals’ valuation of personal data result in scattered, partly contradictious values, depending on the data type, context, and the measurement method. In this study, we aimed to facilitate the valuation for individuals by applying a new and promising measurement methodology: the participants of our field experiment had the chance to sell their selfies in a name-your-own-price auction with repeated bidding and feedback loops. As a result, 39% of our participants were willing to donate or sell their selfies with a median of 5€. Additionally, bidding clusters were identified. Implications for research on the valuation of personal data in terms of privacy are discussed