2,102 Works

Planetary Health for the Arabian Peninsula: The Environmental Limits of Human Population.

Philip M. Mitchell
Human society can be thought of as a heat engine that is powered by fossil fuel and sunlight. The free energy that fossil fuels provide has enabled the development of our modern global human civilization and has artificially raised the human carrying capacity of the planet. Here, I discuss the roots of human population theory in the context of environmental limits, and argue that examining this issue is an essential matter of public health. The...

Design and topological optimization of nanophotonic devices

Ronghui Lin
A central topic in the research of nanophotonics is the geometrical optimization of the nanostructures since the geometries are deeply related to the Mie resonances and the localized surface plasmon resonances in dielectric and metallic nanomaterials. When many nanostructures are assembled to form a metamaterial, the tuning of the geometrical parameters can bring even more profound effects, such as bound states in the continuum (BIC) with infinite quality factors (Q factors). Moreover, with the development...

n-Type Conjugated Polymers for Organic Bioelectronics and Point-of-Care Applications

David Ohayon
Quick and early detection of abnormalities in the body's metabolism is of paramount importance to monitor, control, and prevent the associated diseases and pathologies. Biosensors technology is rapidly advancing, from the first electronic biosensor reported by Clark and Lyons in 1962 for blood glucose monitoring to today’s devices that can detect multiple metabolites in bodily fluids continuously and simultaneously within seconds. This rapid growth in point-of-care devices promises for the development of novel devices with...

A Closer Look at Neighborhoods in Graph Based Point Cloud Scene Semantic Segmentation Networks

Hani Itani
Large scale semantic segmentation is considered as one of the fundamental tasks in 3D scene understanding. Point clouds provide a basic and rich geometric representation of scenes and tangible objects. Convolutional Neural Networks (CNNs) have demonstrated an impressive success in processing regular discrete data such as 2D images and 1D audio. However, CNNs do not directly generalize to point cloud processing due to their irregular and un-ordered nature. One way to extend CNNs to point...

Carbon Dioxide Valorization through Microbial Electrosynthesis in the Context of Circular Bioeconomy

Bin Bian
Microbial electrosynthesis (MES) has recently emerged as a novel biotechnology platform for value-added product generation from waste CO2 stream. Integrating MES technology with renewable energy sources for both CO2 valorization and renewable energy storage is regarded as one type of artificial photosynthesis and a perfect example of circular bioeconomy. However, several challenges remain to be addressed to scale-up MES as a feasible process for chemical production, which include enhanced production rate, reduced energy consumption and...

Metabarcoding and Metagenomic Characterizations of the Red Sea Sector of the Global Dust Belt’s Microbiome

Nojood Aalismail
Atmospheric aerosols have been studied in great depth in regards to its metrological and chemical characterizations. Covering about 33% of the planet, the Global Dust Belt is the major source of wind-blown dust. Airborne aerosols play important roles in the Earth systems, impacting the marine and terrestrial ecosystems, human and organismal health. Aerosolized dust can carry a diverse range of microorganisms that may be transported across large distances. If surviving the transport, influence, as vectors...

Hydrogen Combustion versus Diesel Isobaric Combustion in the Double Compression-Expansion Engine

Rafig Babayev
This thesis aims to contribute to the research and development of a new highly efficient split-cycle engine concept – the double compression-expansion engine (DCEE) – by expanding the knowledge of combustion processes suitable for this and, potentially, other modern engines, via experimental and computational studies. In this work, first, the importance of continued improvement of internal combustion engines is demonstrated by comparing the life-cycle CO2 emissions of different modes of transport, including walking and bicycling....

Seasonal and diel variability of autotrophic and heterotrophic picoplankton in the central Red Sea: Effects of nutrients and temperature

Najwa Aziz Al-Otaibi
Picoplankton, cells between 0.2 - 2 μm, play a vital role in the carbon flow and nutrient cycling in marine food webs. Auto- and heterotrophic picoplankton dominate the biomass of oligotrophic tropical and subtropical oceans. However, little is known about their vertical distribution, changes in space and time and their relationships with environmental variables in the central Red Sea. The goal of this Ph.D. dissertation is to obtain baseline knowledge about their abundance, cellular characteristics...

Exploring the Reactivity of Well-defined Oxide-supported Metal­Alkyl and Alkylidyne Complexes via Surface Organometallic Chemistry

Aya Saidi
Surface Organometallic Chemistry (SOMC) is an excellent approach to erase the gap between homogeneous and heterogeneous catalysis by grafting the molecular organometallic complex on various oxide surfaces, forming well-defined and single-site catalysts. This strategy allows for better characterization as well as the improvement and development of existing and new catalysts. These surface species could promote a wide range of catalytic applications (i.e., metathesis of hydrocarbons, hydrogenolysis of alkanes, and olefin polymerization reactions) depending on the...

Wafer-scale growth method of single-crystalline 2D MoS2 film for high-performance optoelectronics

Xiangming Xu
2D semiconductors are one of the most promising materials for next-generation electronics. Realizing continuous 2D monolayer semiconductors with single-crystalline structure at the wafer scale is still a challenge. We developed an epitaxial phase conversion (EPC) process to meet these requirements. The EPC process is a two-step process, where the sulfurization process was carried out on pre-deposited Mo-containing films. Traditionally, two-step processes for 2D MoS2 and other chalcogenides have suffered low-quality film and non-discontinuity at monolayer...

Increasing the Top Brine Temperature of Multi-Effects Distillation-MED to Boost Its Performance through Controlling the Formation of Scale by Nanofilteration and Antiscalants

Khalid Alharthi
Thermal desalination technology especially, multi-effect distillation MED is of great importance to oil producing countries such as those in the gulf region owing to its efficacy in processing seawater with the minimum pre-treatment of the feed and cheap energy input available from waste heat. One of the main drawback of the current MED processes is the susceptibility of scaling when operate above 70 ºC. This limitation deprives the technology to be energy efficient and reduce...

Shales: Comprehensive Laboratory Characterization

Eduardo Gramajo
Unconventional formations have become an increasingly important source of energy resources. Proper rock mechanic characterization is needed not only to identify the most promising areas for stimulation, but to increase our understanding of the sealing capabilities of cap-rock formations for carbon geological storage. However, shale assessment is challenging with current standard techniques. This research explores the index and rock mechanic properties of different shale specimens considered as source rocks for oil and gas (Eagle Ford,...

The equations of polyconvex thermoelasticity

Myrto Maria Galanopoulou
In my Dissertation, I consider the system of thermoelasticity endowed with poly- convex energy. I will present the equations in their mathematical and physical con- text, and I will explain the relevant research in the area and the contributions of my work. First, I embed the equations of polyconvex thermoviscoelasticity into an aug- mented, symmetrizable, hyperbolic system which possesses a convex entropy. Using the relative entropy method in the extended variables, I show convergence from...

On Using D2D Collaboration and a DF-CF Relaying Scheme to Mitigate Channel Interference

Osama Hassan
Given the exponentially increasing number of connected devices to the network which will lead to a larger number of installed celluar towers and base stations that are in closer proximity to one another when compared to the current cellular network setup, and the increasing demand of higher data rates by end users, it becomes essential to investigate new methods that will more effectively mitigate the larger interference introduced by the more packed celluar grid and...

The effect of aging on the spatial distribution of glycogen in layer I of the somatosensory cortex in mice

Maria Fernanda Veloz Castillo
Astrocytes are the most abundant type of glial cell in the brain, required to ensure optimal neuronal functioning, neurogenesis, and brain vascular tone. Moreover, they play a crucial role in support of neuronal metabolism. The human brain utilizes around 20% of the energy consumed to ensure its proper function. Glucose, an important energy source for the brain, access the neuropil across the blood-brain barrier (BBB), and then is transported into astrocytes through their perivascular end-feet,...

Molecular Modeling of Interfacial, Sorptive, and Diffusive Properties of Systems for Carbon Capture and Storage Applications

Yafan Yang
Carbon capture and storage has been considered as a promising way to mitigate global warming by reducing greenhouse gas emissions. Understanding of the interfacial, sorptive, and diffusive properties of related systems are of significant importance. For example, interfacial tension controls the capillary forces in the caprock, which act to avoid upward migration of the stored fluid and play an important role in related enhanced oil recovery processes. The optimal design of many carbon capture and...

An Empirical Study of the Distributed Ellipsoidal Trust Region Method for Large Batch Training

Ali Alnasser
Neural networks optimizers are dominated by first-order methods, due to their inexpensive computational cost per iteration. However, it has been shown that firstorder optimization is prone to reaching sharp minima when trained with large batch sizes. As the batch size increases, the statistical stability of the problem increases, a regime that is well suited for second-order optimization methods. In this thesis, we study a distributed ellipsoidal trust region model for neural networks. We use a...

Zaxinone, a Natural Apocarotenoid, Regulates Growth and Strigolactone Biosynthesis in Rice

Jian You Wang
Carotenoids are the precursor of several metabolites with regulatory functions, which include the plant hormones abscisic acid (ABA) and strigolactones (SLs), and signaling molecules, such as β-cyclocitral. These carotenoid-derivatives originate from oxidative breakdown of the double bond resulting in carbonyl cleavage-products designated as apocarotenoids. The cleavage reaction causing apocarotenoid formation is catalyzed frequently by Carotenoid Cleavage Dioxygenases (CCDs). Several lines of evidence indicate the presence of yet unidentified apocarotenoids with regulatory or signaling function. Here,...

Effect of Anthropogenic Noise on Reef Macroinvertebrates (Lambis lambis and Tridacna maxima)

Michelle-Nicole Havlik
Boat noise has been shown to distract and cause harm to many marine organisms. Most of the study effort has been focused on fish & marine mammals, even though invertebrates represent 99% of all living organisms, both terrestrial and aquatic. The small amount of studies conducted on invertebrates have demonstrated a clear negative correlation between anthropogenic noise pollution and invertebrate well-being. The small giant clam Tridacna maxima and the spider conch Lambis lambis are two...

Performance comparison of Hierarchical Non-Terrestrial Networks for 6G

Dengke Wang
This thesis investigates the fundamental performance of Hierarchical Non-Terrestrial Networks for the 6th generation (6G). 6G communication research is currently focus- ing on non-terrestrial networks (NTNs) to promote ubiquitous and ultra-high-capacity global connectivity. Specifically, multi-layered hierarchical networks, i.e., the orches- tration among different aerial/space platforms, including Unmanned Aerial Vehicles (UAVs), High Altitude Platforms (HAPs), and satellites co-operating at different al- titudes, currently represents one the most attractive technological options to solve coverage and latency constraints...

Frequency-modulation Stimulated Raman Scattering microscopy with an Acousto-Optic Tunable Filter

Elisa Grassi
Stimulated Raman Scattering (SRS) is a Coherent Raman microscopy method that has been increasingly employed in recent years for highly-specific, label-free, and high-speed bioimaging. Compared to a similar Coherent Raman method, the so-called Coherent Anti-Stokes Scattering (CARS) microscopy, it exhibits advantages such as the absence of nonresonant background (NRB) and the linearity of the signal intensity on the concentration of molecules of interest. However, SRS can be affected by unwanted background signals that hinder the...

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)...

Registration Year

  • 2023
  • 2022
  • 2021
  • 2020
  • 2019
  • 2018

Resource Types

  • Dissertation


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