2,444 Works

Atomic Force Microscopy Characterization of Nanocontacted III nitride Nanostructures

Latifah Almaghrabi
A conductive atomic force microscopy (c-AFM) investigation of GaN nanostructures is reported for strain engineering optoelectronic and piezotronic devices. The use of AFM enables the simultaneous correlation between the surface morphology and charge carrier transport through the nanostructures. The samples under investigation are molecular beam epitaxy (MBE) grown InGaN/GaN nanowires on Ti coated Mo substrate and GaN nanowires on ITO. The metal-semiconductor interface between the metallic substrates and the GaN nanostructures form the bottom contact....

Understanding the molecular functions of the spliceosomal protein SF3B14a/p14 via CRISPR/Cas9 system

Radwa Kamel
At the post-transcriptional level, the splicing of the pre-mRNA plays a vital role in cell fate determination and respond to biotic and abiotic stresses. Through alternative splicing, mRNAs variants can be produced from a single gene. SF3B is a heptameric protein complex that is essential for pre-mRNA splicing. It contains seven subunits: SF3b155, SF3b130, SF3b145, SF3b49, SF3b14b, P14/SF3b14a and SF3b10 and they play an important role in BS (branch point sequence) recognition. P14/SF3b14a interacts with...

Integration Strategy for Standalone Compliant Interactive Systems for Add-on Electronics

Sherjeel M. Khan
Physically compliant (flexible) electronics are scientifically intriguing, mechanically complex, technologically challenging with huge socio-economical potential. The flexible electronics market is expected to grow from USD 23.92 Billion in 2018 to USD 40.37 Billion by 2023. Until now the target applications for flexible electronics have been limited to displays, solar cells, and printed batteries. A fully flexible electronic system can open up a whole new era of novel applications. On the other hand, there has been...

GPS Observations and Modelling of Crustal Deformation in Gulf of Aqaba

Nicolas Castro-Perdomo
The Dead Sea Transform fault (DST) is one of the most prominent tectonic features in the eastern Mediterranean region, located between the Arabian plate and the Sinai sub-plate. Several aspects of this fault system have been thoroughly studied. However, its present-day kinematics along its southern end in Gulf of Aqaba remains poorly understood. This dissertation focusses on crustal motions near Gulf of Aqaba by using geodetic observations and analytical models of crustal deformation. Here we...

Double Compression Expansion Engine: Evaluation of Thermodynamic Cycle and Combustion Concepts

Vijai Shankar
The efficiency of an internal combustion (IC) engine is governed by the thermodynamic cycle underpinning its operation. The thermodynamic efficiency of these devices is primarily determined by the temperature gradient created during the compression process. The final conversion efficiency also known as brake thermal efficiency (BTE) of IC engines, however, also depend on other processes associated with its operation. BTE is a product of the combustion, thermodynamic, gas-exchange, and mechanical efficiencies. The improvement of BTE...

Improvement of Air Gap Membrane Distillation (AGMD) by Peltier’s Effect and Condensation Plate Modifications

Khaled Bin Bandar
Water is undoubtedly a key life element. Its importance is very clear from a religious perspective: “We made from water every living thing. Will they not then believe?” Surah Al-Anbiya verse 30 Also as highlighted in the United Nations resolution 64/292 which recognizes water as a basic necessity for human survival. As the world water demand grows, so does the need to use renewable water sources most available in the form of saline ocean water....

Dissecting JACKDAW transcriptional regulatory module and protein– protein interaction domains

Louai Alidrissi
Many biological processes are regulated via the action of interacting transcription factors. Together, these proteins form a complex regulatory network that will lead to different outcomes according to the DNA context of their target. The transcriptional regulator JACKDAW (JKD) together with the transcription factors SHR (SHORT-ROOT) and (SCARECROW) form a regulatory module that control a variety cell type specific targets to maintain the stem cell niche and regulate asymmetric cell division in the Arabidopsis root...

Mechanism Triggering Pre-Ignition Events and Ideas to Avoid and Suppress Pre-Ignition in Turbocharged Spark-Ignited Engines

Eshan Singh
Turbocharged spark-ignited engines may encounter stochastic events of premature ignition of the fuel-air mixture, termed as pre-ignition. Pre-ignition often leads to extremely high peak pressure and pressure oscillations, causing engine damage. A review of pre-ignition in historic times is done in this dissertation, and the similarities and differences compared to modern pre-ignition issue are brought forth. Experiments conducted with varying injection strategies yielded varying pre-ignition tendency. The pre-ignition tendency correlated with the charge cooling tendency...

Short-read Chromosome Level Genome Assembly of Digitaria exilis

Liubov Gapa
Genomics has become an important tool in agriculture. Many modern crop breeding approaches such as genomic selection and genome editing require detailed information of the genomic composition of a crop species. However, the assembly of high-quality genome sequences is prone to technical artifacts that arise from inaccuracies in the sequencing technology and assembly algorithms. This is particularly true for the genomes of cereal crops, which are often very large, repeat-rich, and polyploid. Until recently, the...

Photosynthetic Oxygenation and Nutrient Utilization by Chlorella vulgaris in a Hybrid Membrane Bioreactor and Algal Membrane Photobioreactor System

Yasmeen Hani Kamal Najm
Aerobic activated sludge membrane bioreactors (AS-MBR) in municipal wastewater treatment are compact systems that can efficiently perform biological organic oxidation. However, aerobic processes require mechanical aeration accounting for over 40% of total expenditure of a wastewater facility. Additionally, a global urgency for nutrient (Nitrogen/Phosphorus) removal strategies due to surges of eutrophication events requires complex MBR configurations. An innovative and cost-effective process was developed with a dual income-stream: high-quality treated effluent and value-added microalgal biomass for...

Photophysics of Organic Molecular Systems – A Study of Excited State Dynamics

Ahmed Balawi
This thesis is dedicated to studies of the excited-state dynamics in organic molecular systems for solar energy conversion by employing time-resolved experimental techniques. Organic photovoltaic (OPV) devices have received significant attention in the past decade and reaching record high power conversion efficiencies (PCE) above 17%. An essential step towards reaching the predicted PCE limit of 25.5% is to develop a comprehensive picture of the photophysical processes, specifically the loss processes, in OPV devices. It is...

Isolation and Characterization of Cellulase-Producing Microorganisms in the Red Sea

Siham Fatani
Cellulase-producing microorganisms are considered as a key player in various environments to degrade the plant biomass and were isolated from various environment like soils, mangroves and oceans. The Red Sea has a unique environment in terms of high seawater temperature, high salinity and low nutrients. This study aims of examining if the Red Sea is a potential resource for cellulase-producing microorganisms and cellulase genes. First, I investigated types of microbial cellulase genes in the Red...

Magnetic Polymer Composite Transducers for Integrated Systems

Mohammed Asadullah Khan
Compact, autonomous computing systems with integrated transducers are imperative to deliver advances in healthcare, navigation, livestock monitoring, point of care diagnostics, remote sensing, internet-of-things applications, smart cities etc. Reflecting this need, there has been sustained growth in the market for transducers. Polymer based transducers, which meld highly desirable properties such as low cost, light weight, high manufacturability, biocompatibility and flexibility, are quite attractive. Doping polymers with magnetic materials results in the formation of magnetic composite...

Characterization of a Novel Nuclear Specific Dicer-isoform in Human Cells

Fatema H. Alquraish
For more than a decade, studies focused on RNA interference (RNAi) pathway as a pivotal gene regulatory mechanism. RNAi components are attracting considerable interest due to the recent evidence demonstrating that they play a role not only in post-transcriptional regulation but also in transcriptional level. The involvement of RNAi components in heterochromatin formation and RNA Pol II processivity and alternative splicing in different organisms has been shown. Dicer protein, a highly conserved protein among kingdoms,...

Analyzing and Manipulating Wave Propagation in Complex Structures

Rasha Al Jahdali
The focus of this dissertation is analyzing and manipulating acoustic wave propagation in metamaterials, which can be used to assist the design of acoustic devices. Metamaterials are artificial materials, which are arranged in certain patterns at a scale smaller than the wavelength and can exhibit properties beyond those naturally occurring materials. With metamaterials, novel phenomena, such as focusing, super absorption, cloaking and localization of ultrasound, are theoretically proposed and experimentally verified. In recent years, a...

Reactivity and Properties of the PN 3P Pincer Platform Insights from Computations and Spectroscopy

Kristin Munkerup
Abstract: Pincer compounds are organometallic complexes with intriguing tunable reactivities. In this work we explore their unique properties and reactivities through spectroscopic and computational investigations, with a focus on the PN3P pincer platform. First, we conducted a computational study on five pincer complexes with stereogenic phosphine arms that have multiple well-defined rotamers. Significant energy differences could be found between the lowest and highest energy rotamer in each set of pincer complexes. All rotamers for reactant,...

Transcriptome of Mycobacterium riyadhense in an in vitro Infection Model

Hanouf Alwajeeh
Mycobacteria is a genus characterized by its unique layer of mycomembrane, which enhances its pathogenicity causing notorious infections such as tuberculosis or leprosy in humans. Some pathogenic mycobacteria are part of the Mycobacterium tuberculosis complex (MTBC), while others are predominantly environmental and belong to the class of non-tuberculosis mycobacteria (NTM). Some of the NTMs are also opportunistic pathogens causing infections mostly in immunocompromised individuals. In this study, we focus on a recently discovered species of...

N-alkylation of amines via dehydrogenative coupling with alcohol catalyzed by the well-defined PN3 rhenium pincer complex

Nasser A. Alobaid
Transition metals are known to be the essential part in most of the catalysts, the heterogeneous and the homogenous catalysts; however, the ligands that attached to the metal centers can also alter the reactivity of the catalyst, and that is widely observed in nature. In our project, we are interested in the metal-ligand cooperation of a special type of ligand called the pincer ligand. Our focus is mainly on the tridentate Pincer Ligands with a...

Theoretical and experimental investigation of liquid droplets flashing for low cost seawater desalination

Raid Alrowais
The high specific energy consumption from all existing seawater desalination methods has heightened the motivation for having more efficient and greener desalination processes to meet the future goals of sustainable seawater desalination. One of the promising thermally-driven desalination methods is the direct-contact spray evaporation and condensation (DCSEC) where the excess enthalpy between feed and equilibrium states of evaporator chambers is exploited with reasonably high flashing efficiency. Further improvements in energy efficacy of DCSEC are boosted...

Advanced Sediment Characterization

Marisol Salva Ramirez
Soil data accumulated during the last century and more recent developments in sensors and information technology prompt the development of new geotechnical solutions for soil assessment. We have advanced three complementary tools: Lab-on-a-Bench, the soil properties database with corresponding IT Tool and the in-situ characterization Multiphysics Probe. Lab-on-a-Bench technology combines cutting-edge sensors and sensing concepts within compact devices and effective laboratory protocols to allow multi physics soil characterization: specific surface measurements for fine-grained soils and...

Fundamental Studies of Soot Formation and Diagnostic Development in Nonpremixed Combustion Environments

Anthony Bennett
Abstract: Soot from combustion emissions has a negative impact on human health and the environment. Understanding and controlling soot formation is desirable to reduce this negative impact, especially as energy demands continue to increase. In this work, a range of fundamental combustion experiments are performed to better understand the soot formation process, and to develop diagnostics for measuring soot properties. First, studies on the effects of doping the flame with different polycyclic aromatic hydrocarbons (PAHs)...

AC ELECTROHYDRODYNAMICS PHENOMENON IN 2D AND 3D MICROELECTRODES

Raphaela Silva
Alternating current electrohydrodynamics (ac-EHD) has been reported as a promising technique for enhancing sensor performance by the intimate mixing of the analyte solution at the electrode surface. The lateral fluid motion created by the ac-EHD phenomenon can be tuned by changing the frequency, voltage, and electrode geometry. To date, various studies have been conducted on the use of 2D electrodes based ac- EHD devices for sensor applications. However, the use of 3D electrodes may provide...

Optimization for Supervised Machine Learning: Randomized Algorithms for Data and Parameters

Filip Hanzely
Many key problems in machine learning and data science are routinely modeled as optimization problems and solved via optimization algorithms. With the increase of the volume of data and the size and complexity of the statistical models used to formulate these often ill-conditioned optimization tasks, there is a need for new efficient algorithms able to cope with these challenges. In this thesis, we deal with each of these sources of difficulty in a different way....

Interfacially Polymerized Thin-Film Composite Membranes Based on Biophenolic Material for Liquid Separation

Banan O. Alhazmi
Abstract: The aim of this research is to fabricate thin-film composite (TFC) membranes using a synthetic derivative of plant-based phenols, as a non-toxic building block for interfacial polymerization. Classical interfacially polymerized composite membranes are heavily integrated in reverse osmosis and nanofiltration applications for water and wastewater treatment and most recently for chemical and pharmaceutical industries. Implementing sustainable practices in membrane fabrication by exploiting greener alternatives to conventional chemicals can directly reduce hazardous waste and ultimately...

Ignition Delay Data Set

S.M. Almohammadi, Omar Knio & O.P. Le Maître
This data file has 38,311 lines. Each line contains 3812 entries. The first 3811 entries on each line correspond to the coordinates of a random vector, whose components are independent and uniformly distributed in [-1,1]. The last entry on each line is the quantity of interest (QoI), namely the ignition delay time (s). The simulations are described in S.M. Almohammadi, O.P. Le Maitre, O.M. Knio (2020) "Computational Challenges in Sampling and Representation of Uncertain Kinetic...

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