227 Works

The role of NAC transcription factors in responses of plants to heat and salt stresses

Nouf Owdah Hameed Alshareef
Soil salinity and heat stress are two major abiotic stresses affecting plant growth and yield. Transcription factors (TFs) are key regulators in stress responses. They link stress sensing with many tolerance mechanisms by translating stress signals into changes in gene expression that ultimately contribute to stress tolerance. The NAC (NAM, ATAF and CUC) TF family have been found to be involved in responses to biotic and abiotic stresses. In this PhD project, the role of...

A Computational Investigation of Multiple Injection Strategy in an Isobaric Combustion Engine

Hammam H. Aljabri
Abstract: This thesis aims to contribute to the development of the isobaric combustion engines by exploring multiple injection strategies, by means of computational simulations using a commercial software Converge. A single injection case validated with experimental data in terms pressure trace and heat release rate was used as a baseline reference. The adjustment of the turbulent kinetic energy dissipation constant is found to have the most significant influence in reproducing the pressure and heat release...

Toward selective H2 evolution from overall water splitting and the trifluoromethylation of heteroarenes via heterogeneous photocatalysis

Muhammad Qureshi
Converting solar energy into useful chemical bonds via photocatalysis is a growing field aimed at addressing global challenges. The research disclosed describes heterogeneous photocatalysis as a nanophotoelectrochemical cell as photocatalysts enable both reduction and oxidation reactions using the local charge separation of photo-excited carriers. Herein, experimental and theoretical results of nanoscale electrolysis of water on the surface of CrOx/Pt/SrTiO3 showed that ohmic losses are negligible when the anode and cathode are within nanometer distances from...

Leader-Follower Approach with an On-board Localization Scheme for Underwater Swarm Applications

Sarah Toonsi
A striking feature of swarm robotics is its ability to solve complex tasks through simple local interactions between robots. Those interactions require a good infrastructure in communication and localization. However, in underwater environments, the severe attenuation of radio waves complicates communication and localization of different vehicles. Existing literature on underwater swarms use centralized network topology which require physical vicinity to the central node to ensure reliability. We are interested in building a decentralized underwater swarm...

Detection of Pre-ignition Events using Deep Neural Networks

Nursulu Kuzhagaliyeva
Abstract: Engine downsizing and boosting have been some of the most widely used strategies for improving engine efficiency in recent years. Several studies have offered significant departures from on-road pre-ignition to steady-state engine laboratory studies, necessitating more robust data-driven diagnostic tools that can identify pre-ignition events in real world environments. The goal of this study is to apply deep neural networks for pre-ignition (PI) detection, based on scientific data obtained from less expensive sensors (like...

Biofouling in anaerobic membrane bioreactors: To control or not to?

Hong Cheng
Anaerobic membrane bioreactor (AnMBR) serves as a more sustainable form of wastewater treatment. However, biofouling is particularly detrimental to the performanceof AnMBRs. This dissertation focuses on understanding more about the biofouling in nMBR, and to devise strategies to control or make use of these biofoulant layers. First, we aim to investigate the microbial community structure of sludge and biofilm from 13 different AnMBRs. Our findings indicate 20 sludge core genera and 12 biofilm core genera...

Traffic Monitoring and MAC-Layer Design for Future IoT Systems

Enas M. Odat
The advances in the technology and the emergence of low complexity intelligent devices result in the evolution of the Internet-of-Things (IoT). In most IoT application scenarios, billions of things are interconnected together using standard communication protocols to provide services for different applications in the healthcare industry, smart cities, transportation, and food supply chain. Despite their advantage of connecting things anywhere, anytime, and anyplace, IoT presents many challenges due to the heterogeneity, density, the power constraints...

‘Allelofertile’ soil islands self-conditioned by Welwitschia mirabilis in the Namib Desert

Dalia H. Shabaan
Under the extreme arid conditions of deserts, long periods of drought, nutrient-poor soils and high temperatures severely challenge the primary productivity of the ecosystem. Desert plants have evolved morphological and physiological adaptations against abiotic stresses. Along with these adaptation strategies they can recondition their surrounding soil, which will result in the enrichment of nutrients and moisture in the soil surrounding the plant. Although such self-fertilization may support the growth of other sympatric plant species under...

Expression of EZH1-Polycomb Repressive Complex 2 and MALAT1 lncRNA and their Combined Role in Epigenetic Adaptive Response

Lamya Al Fuhaid
Living cells maintain stable transcriptional programs while exhibiting plasticity that allows them to respond to environmental stimuli. The Polycomb repressive complex 2 (PRC2) is a key regulator of chromatin structure that maintains gene silencing through the methylation of histone H3 on lysine 27 (H3K27me), establishing chromatin-based memory. Two variants of PRC2 are present in mammalian cells, PRC2-EZH2 which is predominantly present in differentiating cells, and PRC2-EZH1 that predominates in post-mitotic tissues. PRC2-EZH1α/β pathway is involved...

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,...

Registration Year

  • 2019

Resource Types

  • Dissertation


  • King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia