Studies of silicon photoelectrochemical cells under high injection conditions

The behavior of Si/CH3OH-dimethylferrocene+/0 junctions has been investigated under high injection conditions. Open circuit voltages of (626±5) mV were obtained at short circuit photocurrent densities of 20 mA/cm^2 for samples with an n + -diffused back region, point contacts on the back surface, and with a base of thickness 390 µm and a 1 ms hole lifetime. The diode quality factor and recombination current density were 1.8±0.1 and (2.6±1.5)×10–8 A/cm^2, respectively. These data are consistent with recombination dominated by the base and back contact regions, and not at the Si/CH3OH interface

Fast Monte-Carlo Localization on Aerial Vehicles using Approximate Continuous Belief Representations

Size, weight, and power constrained platforms impose constraints on computational resources that introduce unique challenges in implementing localization algorithms. We present a framework to perform fast localization on such platforms enabled by the compressive capabilities of Gaussian Mixture Model representations of point cloud data. Given raw structural data from a depth sensor and pitch and roll estimates from an on-board attitude reference system, a multi-hypothesis particle filter localizes the vehicle by exploiting the likelihood of the data originating from the mixture model. We demonstrate analysis of this likelihood in the vicinity of the ground truth pose and detail its utilization in a particle filter-based vehicle localization strategy, and later present results of real-time implementations on a desktop system and an off-the-shelf embedded platform that outperform localization results from running a state-of-the-art algorithm on the same environment

Numerical Modeling of the Flow of Fluids and Energy in EOR Injection Wells Using PROSPER

This report is written to mainly discuss about the final year project entitled “Numerical Modeling of the flow of fluids and energy in Enhanced Oil Recovery (EOR) injection wells using PROSPER”. Oil and gas industries are looking for new ways to maximize their production and at the same time maximize their profit. One of the main focuses of all the oil and gas industries is increasing the recovery of the oil and gas using Enhanced Oil Recovery (EOR) method. Steam injection is one of the EOR methods that have been given higher priority by oil and gas industries. Many researchers have done the study on the heat losses along the wellbore during the steam injection. In this project, heat losses have been calculated using PROSPER software which in one of the commercial software used by oil and gas industries. The main purpose of this study is to calculate the heat losses, pressure losses, temperature losses, and steam quality changes along the wellbore during steam injection. Increment or decrement of the fluid temperature will directly affect the energy that going to be transferred to the production fluid. Wellbore cement failure due to the higher temperature along the wellbore can be avoided once the heat losses are known. The results that have been obtained from this project work clearly shows the amount of heat losses to the formation and how it affect steam quality, temperature, pressure of injected steam. Greater heat losses can be avoided using insulation material in the wellbore. The optimum injected steam temperature and pressure as well as steam quality at the wellhead can be calculated once the amount of energy of the steam is known at the bottomhole. Cement failure can be prevented by using the proper cement to counter the effect of the heat. Taking into the consideration the effect of friction and slippage effect between phases, PROSPER can accurately calculate the heat losses that occurs in the wellbore

Fabrication of minority-carrier-limited n-Si/insulator/metal diodes

A photoelectrochemical anodization technique has been used to fabricate n-Si/insulator/metal (MIS) diodes with improved electrical properties. MIS structures fabricated with Au have provided the first experimental observation of a solid-state n-Si surface barrier device whose open circuit voltage Voc is controlled by minority-carrier bulk diffusion/recombination processes. For these diodes, variation of the minority-carrier diffusion length and majority-carrier dopant density produced changes in Voc that were in accord with bulk diffusion/recombination theory. Additionally, the variation in Voc in response to changes in the work function of the metal overlayer indicated that these MIS devices were not subject to the Fermi level pinning restrictions observed for n-Si Schottky structures. X-ray photoelectron spectroscopic characterization of the anodically grown insulator indicated 8.2±0.9 Å of a strained SiO2 layer as the interfacial insulator resulting from the photoanodization process