240 Works

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...

Poly Silicon on Oxide Contact Silicon Solar Cells

Jingxuan Kang
Silicon photovoltaic (PV) is a promising solution for energy shortage and environmental pollution. We are experiencing an era when PV is exponentially increasing. Global cumulative installation had reached 380 GW in 2017. Among which, silicon-based PV productions share more than 90% market. Performance of the first two-generation commercial popular silicon solar cells - Al-BSF and PERC - are limited by metal/Si contacts, where interface defects significantly reduce the open-circuit voltage. In this context, full-area passivation...

Dynamics and Nonlinear Interactions of Macro and Micro Structures: Inclined Marine Risers and MEMS Resonators

Feras Alfosail
This work presents a combination of analytical and numerical approaches to gain an insight of the dynamics of marine risers and micro machined resonators. Despite their scale difference, we show that both systems share similarities in terms of initial static deformation, quadratic and cubic nonlinearities, and internal resonances. First, we utilize the state space method to study the eigenvalue problem of vertical riser. An orthonormalization step is introduced to recover the numerical scheme during numerical...

Synthesis, Characterization and Reactivity of Manganese PN3 Pincer Complexes

Razan Mal
Manganese is amongst the most abundant transition metals on earth. Playing several roles in enzymatic function, manganese is largely considered biocompatible and, in comparison to most transition metals, it is relatively inexpensive. It is surprising then, that manganese remains poorly explored in the field of pincer-based homogenous catalysis. PN3(P) pincer ligands have proved to impart different kinetic and thermodynamic properties to the complexes they are a part of when compared to analogous complexes of ligands...

Multiscale Hybridization towards Efficient Oil and Gas Flows Simulations within Fractured Rocks

Sahar Amir
Fractures impact the geological systems remarkably. So, their effects are included within the mathematical simulation models. Literature simulation schemes either lose the facture characteristics or are effort and time-consuming. So Hybrid-Fracture schemes are developed to overcome these drawbacks. In the dissertation, a generalized Hybrid-Embedded Fractures (HEF) scheme is developed. It establishes a hierarchical classification based on fracture length's relation to uniform grid-cell lengths. Tall and medium-length fractures are detected from images, classified using Machine-Learning (ML)...

Sim-to-Real Transfer for Autonomous Navigation

Matthias Müller
This work investigates the problem of transfer from simulation to the real world in the context of autonomous navigation. To this end, we first present a photo-realistic training and evaluation simulator (Sim4CV)* which enables several applications across various fields of computer vision. Built on top of the Unreal Engine, the simulator features cars and unmanned aerial vehicles (UAVs) with a realistic physics simulation and diverse urban and suburban 3D environments. We demonstrate the versatility of...

Arrival-time picking methodology using fuzzy c-means and Akaike information criterion for downhole microseismic data

Eduardo Valero Cano
Microseismic monitoring is a valuable technique to locate and characterize frac- tures in unconventional reservoirs. The monitoring is usually carried out from a large surface array of vertical-component receivers or a short downhole array of three- component receivers. For a downhole array, P- and S-wave arrival-time picking is typically required to process the microseismic data. Furthermore, arrival-time pick- ing is done automatically considering the large volumes of microseismic data. In this work, I propose a...

Full-waveform inversion for large 3-D salt bodies

Mahesh Kalita
The ever-expanding need for energy, including those related to fossil fuels, is behind the drive to explore more complicated regions, such as salt and subsalt provinces. This exploration quest relies heavily on recorded surface seismic data to provide precise and detailed subsurface properties. However, conventional seismic processing algorithms including the state-of-the-art full-waveform inversion (FWI) fail to recover those features in many areas of salt provinces. Even the industrial solution with substantial involvement of manual human-interpretation...

Towards Multistate Magnetic Tunnel Junctions for Memory and Logic Applications

Ulan Myrzakhan
For many decades, the revolution in semiconductor industry has continuously been powered by the successful down scaling of complementary metal-oxide semiconductor (CMOS) technology to produce integrated circuits with improved performance at lower cost. However, current charge-based CMOS technology is already approaching physical limits and, thus, encounters a number of technological challenges. Spintronics is an emerging and rapidly evolving research field that has a great potential to overcome these challenges confronting CMOS by introducing the electron...

Comparison of avirulent pathogen Pseudomonas syringae and beneficial Enterobacter sp SA187 for enhancing salt stress tolerance in Arabidopsis thaliana

Rewaa S. Jalal
Abiotic stresses such as salt stress are the major limiting factors for agricultural productivity, and cause global food insecurity. It is well known that plant associated beneficial microorganisms can stimulate plant growth and enhance resistance to abiotic stresses. In this context, bacterial endophytes are a group of bacteria that colonize the host plant and play a fundamental role in plant growth enhancement under stress condition. Recently, our group reported that the beneficial bacteria Enterobacter sp.SA187...

Investigating Semiconductor Nanostructures Functionalized by Emerging Materials for Optoelectronic Devices

Norah M. Alwadai
Wide and direct bandgap semiconductors (WBSs) are promising materials for many deep UV (DUV) applications. However, several challenges presently hinder the enhancement of DUV optoelectronics, such as low crystal quality, as well as complex and costly fabrication and growth processes that prevent production of high-performance devices, especially for large-scale applications. As a part of the study reported in this dissertation, I demonstrate several novel WBS-based devices with improved or novel functionalities, for the first time....

Seawater-induced Biofouling in Direct Contact Membrane Distillation

Sarah A. Alsaidalani
Membrane distillation (MD) is a promising desalination technology which allows to achieve high salt rejection at low energy expenses as compared to conventional desalination processes. However, just like in any other membrane separation process, the MD membrane is susceptible to biofouling which is one of the critical problems in membrane-based systems. In this study, we investigated the effects of spacer design and feed temperature on the biofilm formation and proliferation in a flat-sheet direct contact...

Object Detection Using Multiple Level Annotations

Mengmeng Xu
Object detection is a fundamental problem in computer vision. Impressive results have been achieved on large-scale detection benchmarks by fully-supervised object detection (FSOD) methods. However, FSOD approaches require tremendous instance-level annotations, which are time-consuming to collect. In contrast, weakly supervised object detection (WSOD) exploits easily-collected image-level labels while it suffers from relatively inferior detection performance. This thesis studies hybrid learning methods on the object detection problems. We intend to train an object detector from a...

Making a Model - Investigating the Molecular Machinery of the Coral Symbiosis Model System Aiptasia

Maha Joana Cziesielski
Coral reefs are the most diverse marine ecosystems of significant ecological and economic importance, globally. Increasing environmental stress imposed by global warming, ocean acidification and pollution has led to the continuous decline of coral reefs. For reefs to thrive and survive, they rely on the stable endosymbiosis between coral animal and photosynthetic algae. The fragile symbiotic relationship is dependent on a balanced metabolic exchange, which is easily disturbed by stress, consequently leading to the loss...

Inkjet Printing of a Two-Dimensional Conductor for Cutaneous Biosignal Monitoring

Abdulelah Saleh
Wearables for health monitoring are rapidly advancing as evidenced by the number of wearable products on the market. More recently, the US Food and Drug Administration approved the Apple Watch for heart monitoring, indicating that wearables are going to be a part of our lives sooner than expected. However, wearables are still based on rigid, conventional electronic materials and fabrication procedures. The use of flexible conducting materials fabricated on flexible substrates allows for more comprehensive...

High-Performance Polyimide Gas Separation Membranes Based on Triptycene Dianhydrides and Di-Hydroxy-Diamino-Triptycene Monomers.

Abdulaziz Q. Alqahtani
Distillation technology involves capital- and energy-intensive processes for light olefin/paraffin separation. Global demand for propylene has already exceeded 110 million tons per year. Therefore, distillation processes used for the separation of C3H6/C3H8 should be replaced or debottlenecked with more efficient and cost-effective technology. In the last three decades, membrane-based gas separation processes have successfully emerged, thus competing with conventional separation processes. Membranes potentially offer lower capital investment and operation cost than distillation columns. In this...

Application of Quantitative Phosphoproteomics to the Study of Cnidarian-Dinoflagellate Symbiosis

Fabia Simona
Corals are cnidarian animals that build the founding structures of tropical reefs, which survival depends upon the obligate symbiotic association to photosynthetic dinoflagellate algae in the family Symbiodiniaceae. As corals are facing increasing environmental and anthropogenic stress, understanding the molecular principles governing this unique symbiotic association is crucial to predict their adaptive potential. Due to logistic, costly, and experimental difficulties of working with corals, we use the sea anemone Aiptasia (sensu Exaiptasia pallida) as a...

Development of bismuth (oxy)sulfide-based materials for photocatalytic applications

Amal BaQais
Technologies based on alternative and sustainable energy sources present a vital solution in the present and for the future. These technologies are strongly driven by the increased global energy demand and need to reduce environmental issues created by fossil fuel. Solar energy is an abundant, clean and free-access resource, but it requires harvesting and storage for a sustainable future. Direct conversion and storage of solar energy using heterogeneous photocatalysts have been identified as parts of...

Semantic Prioritization of Novel Causative Genomic Variants in Mendelian and Oligogenic Diseases

Imene Boudellioua
Recent advances in Next Generation Sequencing (NGS) technologies have facilitated the generation of massive amounts of genomic data which in turn is bringing the promise that personalized medicine will soon become widely available. As a result, there is an increasing pressure to develop computational tools to analyze and interpret genomic data. In this dissertation, we present a systematic approach for interrogating patients’ genomes to identify candidate causal genomic variants of Mendelian and oligogenic diseases. To...

Highly efficient photoleletrochemical water splitting by optical, electrical and catalysis concurrent management

Hui-Chun Fu
One way of harnessing and storing our most abundant and renewable energy source, sunlight, is by utilizing it to split water for the hydrogen generation as a storable form of fuel. Si, the most investigated material for solar-to-hydrogen technology has great potential as the single photoelectrode. While some success has been achieved in Si-Based photoelectrochemical (PEC) systems, they suffer from low efficiency and short longevity. Moreover, in order for hydrogen to be commercially viable, the...

Algorithms and Frameworks for Graph Analytics at Scale

Fuad Tarek Jamour
Graph queries typically involve retrieving entities with certain properties and connectivity patterns. One popular property is betweenness centrality, which is a quantitative measure of importance used in many applications such as identifying influential users in social networks. Solving graph queries that involve retrieving important entities with user-defined connectivity patterns in large graphs requires efficient com- putation of betweenness centrality and efficient graph query engines. The first part of this thesis studies the betweenness centrality problem,...

Investigation of Zinc Interactions to Human Serum Albumin and Their Modulation by Fatty Acids

Samah Al-Harthi
Zinc is an essential metal ion for the activity of multiple enzymes and transcription factors. Among many other transporting proteins human serum albumin (HSA) is the main carrier of Zn(II) in the blood plasma. HSA displays multiple ligand binding sites with extraordinary binding capacity for a wide range of ions and molecules including fatty acids. Hence, HSA controls the availability and distribution of those molecules throughout the body. Previous studies have established that the existence...

Identification, validation and characterization of putative cytosolic and nuclear targets of immune MAPKs involved in biotic stress responses in Arabidopsis thaliana

Hanna Alhoraibi
Plants are sessile organisms and constantly encounter a myriad of pathogens; therefore, they rely on highly effective defense system for their survival. Our understanding of how plant immunity is triggered and regulated has seen tremendous progress over the last two decades, with many important players identified in the model systems, Arabidopsis thaliana. Mitogen activated protein kinases play a central role in signal transduction in biotic and abiotic stresses. MAPK pathways are regulated by three-interlinked protein...

Registration Year

  • 2019

Resource Types

  • Dissertation
  • Dataset
  • Software
  • Other


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