I dedicate this thesis to my beautiful mother, Maryam, who supported me with her unconditional lo... more I dedicate this thesis to my beautiful mother, Maryam, who supported me with her unconditional love, continuous prayers and encouragement. And to my loving husband, Meshari, who always believed in me, and never stopped supporting me.
A computational algorithm to model a coupled solar-hydrogen system is presented. The results demo... more A computational algorithm to model a coupled solar-hydrogen system is presented. The results demonstrated that optimizing the system's cost and hydrogen production rate implicitly ensures the levelized cost of energy is minimized.
13th International Symposium on Process Systems Engineering (PSE 2018), 2018
Abstract The objective of this work is to develop computational tools to identify optimal configu... more Abstract The objective of this work is to develop computational tools to identify optimal configurations when integrating a large number of solar cells under shady or faulty conditions. The photovoltaic module that will be considered in this analysis consists of 96 cells connected in series, where an equal number of solar cells, called a string, is connected to a bypass diode. Both event-driven Monte Carlo simulation and Multi- Attribute Utility Theory are used to evaluate the effect of the number of bypass diodes on the photovoltaic module maximum power point, and to find the optimal configuration needed to minimize performance losses under uncertain shading conditions. The optimal cell configuration is established when the total value function of the module is maximized. Ideally, it was found that the optimal situation corresponds to having one bypass diode connected to each cell in the module; however, by factoring in diode cost, it was found that one bypass diode wired to each group of four solar cells was economically more practical.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights • A species-reaction graph approach for extracting reaction invariants is presented • Reaction invariants being semi-positive facilitate their physical interpretation • Semi-positive invariants can signal potential defects in a reaction network • An algorithm to automate the generation of the semi-positive invariants is presented • This approach is applicable to different processes including atom free stoichiometries
The mechanism and kinetics of hydrogen evolution (HER) and oxygen evolution (OER) reactions on ni... more The mechanism and kinetics of hydrogen evolution (HER) and oxygen evolution (OER) reactions on nickel iron layered double hydroxide (NiFe LDH) in a basic electrolyte are investigated. The deposited film reported an overpotential of 247 and 245 mV at 10 mA/cm 2 toward the HER and OER, respectively. A least squares procedure was performed to fit a theoretical current density model with experimental linear sweep voltammetry (LSV) results, and the chemical reaction rate constants for the OER and HER steps were identified. Electrochemical impedance spectroscopy (EIS) measurements were taken at different potentials, and the resulting kinetic model demonstrates a good agreement between theoretically calculated faradaic resistance and experimental EIS results. The HER results indicated the Heyrovsky step as rate controlling, with a dependence of reaction mechanism on potential. At low potential, the mechanism begins with a Volmer step, followed by parallel Tafel and Heyrovsky steps. At higher potential, the mechanism becomes consecutive combination of the Volmer and Heyrovsky steps. The OER data point to the formation of the adsorbed peroxide as rate controlling. The HER and OER kinetic data were combined into a model capable of predicting the electrolysis cell current-potential characteristics, which can be used for process design and optimization.
I dedicate this thesis to my beautiful mother, Maryam, who supported me with her unconditional lo... more I dedicate this thesis to my beautiful mother, Maryam, who supported me with her unconditional love, continuous prayers and encouragement. And to my loving husband, Meshari, who always believed in me, and never stopped supporting me.
A computational algorithm to model a coupled solar-hydrogen system is presented. The results demo... more A computational algorithm to model a coupled solar-hydrogen system is presented. The results demonstrated that optimizing the system's cost and hydrogen production rate implicitly ensures the levelized cost of energy is minimized.
13th International Symposium on Process Systems Engineering (PSE 2018), 2018
Abstract The objective of this work is to develop computational tools to identify optimal configu... more Abstract The objective of this work is to develop computational tools to identify optimal configurations when integrating a large number of solar cells under shady or faulty conditions. The photovoltaic module that will be considered in this analysis consists of 96 cells connected in series, where an equal number of solar cells, called a string, is connected to a bypass diode. Both event-driven Monte Carlo simulation and Multi- Attribute Utility Theory are used to evaluate the effect of the number of bypass diodes on the photovoltaic module maximum power point, and to find the optimal configuration needed to minimize performance losses under uncertain shading conditions. The optimal cell configuration is established when the total value function of the module is maximized. Ideally, it was found that the optimal situation corresponds to having one bypass diode connected to each cell in the module; however, by factoring in diode cost, it was found that one bypass diode wired to each group of four solar cells was economically more practical.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights • A species-reaction graph approach for extracting reaction invariants is presented • Reaction invariants being semi-positive facilitate their physical interpretation • Semi-positive invariants can signal potential defects in a reaction network • An algorithm to automate the generation of the semi-positive invariants is presented • This approach is applicable to different processes including atom free stoichiometries
The mechanism and kinetics of hydrogen evolution (HER) and oxygen evolution (OER) reactions on ni... more The mechanism and kinetics of hydrogen evolution (HER) and oxygen evolution (OER) reactions on nickel iron layered double hydroxide (NiFe LDH) in a basic electrolyte are investigated. The deposited film reported an overpotential of 247 and 245 mV at 10 mA/cm 2 toward the HER and OER, respectively. A least squares procedure was performed to fit a theoretical current density model with experimental linear sweep voltammetry (LSV) results, and the chemical reaction rate constants for the OER and HER steps were identified. Electrochemical impedance spectroscopy (EIS) measurements were taken at different potentials, and the resulting kinetic model demonstrates a good agreement between theoretically calculated faradaic resistance and experimental EIS results. The HER results indicated the Heyrovsky step as rate controlling, with a dependence of reaction mechanism on potential. At low potential, the mechanism begins with a Volmer step, followed by parallel Tafel and Heyrovsky steps. At higher potential, the mechanism becomes consecutive combination of the Volmer and Heyrovsky steps. The OER data point to the formation of the adsorbed peroxide as rate controlling. The HER and OER kinetic data were combined into a model capable of predicting the electrolysis cell current-potential characteristics, which can be used for process design and optimization.
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Papers by Aisha Alobaid