Ritu Raj Singh

Parametric Analysis of Silicon Nanowire Optical Rectangular Waveguide Sensor

A silicon nanowire optical rectangular waveguide (SNORW) on 220-nm silicon-on-insulator platform is proposed for optical sensing of gases. Analysis and interdependence of critical parameters of SNORW are evaluated. Overall performance in terms of power confinement, waveguide sensitivity, and compactness is compared with that of conventional slot and ridge slot waveguides. Exploratory results on SNORW application as methane sensor are also discussed.

ENHANCED HYDROCARBON EXTRACTION FROM CALOTROPIS PROCERA - A PETROCROP

ABSTRACT With fast disappearing petroleum reserves renewable resources like biomass are of great significance. Petrocrop, Calotropis procera is a wild shrub and does not compete with food and fodder crops for land. This paper presents an investigation on enhancement of hydrocarbon extraction from Calotropis procera. An extraction yield of 8% has been obtained with toluene, as solvent. Increase in extraction to 11.5% has been achieved by modification of design of conventional “Soxhlet extractor”. Further enhancement in extraction has been achieved by pre-treatment of the biomass with alkali or acid. Pre-treatment results in extractive or hydrolytic breakdown of plant structure and hence exposes hyrocarbons to solvent attack. Alkali pretreatment of ground biomass resulted in much higher extraction. So it was studied in further detail with more alkalies of varying strength. An enhancement from 8% to 18% has been achieved by pre-treatment with IN sodium hydroxide.

SNORW biosensor for measuring glucose level in blood samples

A silicon nanowire waveguide based glucose sensor has been proposed and analyzed. It uses minimal invasive approach to measure the glucose level in a very small blood sample, where, Ethylene-diamine-tetraacetic acid (EDTA) as an anticoagulant, sodium fluoride as preservative and blood sample measurand are added in the ratio of 8:1:1. As the glucose concentration in the blood sample varies, the refractive index (RI) of blood changes, accordingly the refractive index of the solution with 10% blood also gets altered, which in turn to deviated response of the biosensor. The prediction of glucose level is affirmed by taking this solution as a cladding measurand of waveguide. Silicon Nanowire Optical Rectangular Waveguide (SNORW) is proposed for the first time in bio-sensing application for the detection of blood glucose. It works on the principle of detecting changes in refractive index for various concentrations of glucose level ranging from 10 mg/dl to 200 mg/dl. Additionally, SNORW sensor characteristics are compared accordingly with the slot waveguide sensors.