Ehsan Ul Haq

Effect of leaching with 5-6 N H2SO4 on thermal kinetics of rice husk during pure silica recovery.

Rice husk is a potential source for renewable energy and silica. To extract the maximum amount of silica, usually the rice husk is treated with strong acids that burn the organic part leaving behind a black residue. In this research, sulfuric acid is used as an oxidizing agent. Efforts are focused to find out more about the behavior of acid-treated rice husk by using thermal exposure, and results are compared with results for raw rice husk which is thermally exposed but not acid treated. Reaction ratio of rice husk combustion and energy of activation were calculated using the thermogravimetric data. Acid treatment was found influential in initiating degradation earlier compared to raw husk and an overall increase in value of activation energy was observed when heating rate was increased.

Investigation of Various Nano-Structural Morphologies of Zinc Oxide for their Applications in Dye-Sensitized Solar Cells

In the current study, various morphologies of zinc oxide (ZnO) including nanorods, nanoflowers, nanosheets/flakes, nanospherical particles, nanohexagonal sheets, and nanoneedles have been prepared by using single step and two-step hydrothermal processes with optimized parameters such as growth temperature, growth time and compositions of both the seed and growth solutions. Fluorine doped tin oxide (FTO) coated glass was used as the substrate. The prepared morphologies were characterized with the help of scanning electron microscopy (SEM) and the purity of nanostructures was confirmed by elemental analysis (EDX). These nanostructures were used as photo-anode material to fabricate the DSSC using a dye (Rhodamine B) for enhancing the range of solar spectrum that is to be adsorbed. Finally the fabricated solar cells were characterized in terms of their efficiency, gauged by their fill factor. Among different morphologies investigated as photo anode materials; nanosheets/flakes were found to be showing maximum efficiency, with fill factor values around 0.5 due to their larger surface area, better porosity and enhanced capability of light trapping and scattering.

Break Index (BI) annotated speech corpus for Urdu TTS

This study presents 10 hours of speech corpus annotated at Break Index (BI) level for Urdu text to speech system (TTS). For the speech corpus annotation, 5-steps scale of BI is presented in this study, which assists us to understand the prosodic relationship between word boundaries and phrase boundaries in Urdu. Moreover, an algorithm for Urdu TTS is designed to detect the 5-steps scale of BI automatically using acoustic cues such as duration of phrasal breaks, intonational patterns, glottalization and phrase lengthening. This algorithm annotates 10 hours of speech automatically and reports 98.4% accuracy compared to perceptual marked BI. This research also discusses the controversial issue of prosody to syntax mapping and syntax to prosody mapping in Urdu. The results indicate: (i) in the context of noun phrase and case phrase (NP-KP), prosodic break occurs between NP-KP to eliminate syntactic ambiguity; (ii) string of KPs does not require explicit prosodic break because case markers act as phrase separators in KP-KP context (iii) verb phrase (VP) in an utterance is preceded by a prosodic break to differentiate it from other phrases in an utterance and (iv) NPs of complex predicates prosodically act as single unit in an utterance.