2,378 Works

Metathesis of functionalized alkanes: understanding the unsolved problem

Mykyta Tretiakov
The aim of this dissertation is to discover the metathesis of functionalized alkane. The first chapter describes an overview of the catalysis field, the role of surface organometallic chemistry (SOMC) and the history of metathesis. The second chapterstudies the decomposition of the alkane metathesis catalyst precursor based on WMe6 grafted on partially dehydroxylated at 700 °C silica (SiO2-700) [≡Si-O-WMe5] and its activity in the metathesis of non-coordinating substrates. We used thermal programmed desorption (TPD), in...

Monte-Carlo Based Laminar Flame Speed Correlation for Gasoline

Ahmed A. Harbi
Gasoline is a complex fuel containing hundreds of species, and, therefore, it is quite difficult to model all components present in gasoline. Alternatively, researchers tend to employ simpler surrogates that mimic targeted physical and chemical properties of gasoline. Two properties of gasoline, i.e., autoignition and laminar flame speed, play key role in the overall performance of spark-ignition and modern engines. For fuel-engine optimization, it is very important to have simple models which can accurately predict...

Organic Semiconductor Nanoparticle Photocatalysts for Hydrogen Evolution from Water

Jan Kosco
Photocatalytic water splitting using solar irradiation has the potential to produce sustainable hydrogen fuel on a large scale. Practical solar energy conversion requires the development of new, stable photocatalysts that operate efficiently under a broad range of visible wavelengths. Organic semiconductors are increasingly being employed as photocatalysts due to their earth abundance, aqueous stability, and optical absorptions that can be tuned to the solar spectrum. However, much remains unknown about the mechanism of organic semiconductor...

Communication Through Breath Using Molecular Communication Modeling in Indoor Environments

Nojood Almayouf
The concept of communication via breath is introduced under the molecular com munication system, where data can be exchanged through inhalation and exhalation. Those data are carried by volatile organic compounds (VOCs) or pathogens and transferred through an aerosol channel. In this thesis, we propose a molecular com munication model for an instantaneous source in a bounded indoor environment. The walls of this environment could be reflectors and/or absorbers by adjusting the value of deposition...

Atomically Precise Silver Nanoclusters: Controlled Synthesis and Assembly into Structurally Diverse Frameworks with Tailored Optical Properties

Mohammad Jaber Alhilaly
Ligand-protected metal nanoclusters (NCs), which are ultra-small nanoparticles marked by their atomic precision, are distinctly importance for contemporary nanomaterials. NCs have attracted significant research attention for utilizing their novel optical and physicochemical properties in various applications, including fluorescence sensing, catalysis, and biomedical applications. This dissertation deals with ligand-protected atomically precise silver NCs and is divided into two main parts. The first part is focused on the exploration and design of well-defined silver NCs through surface...

Investigating The Molecular Functions of The Os-Sc106 Spliceosomal Protein Via CRISPR/Cas9 System

Abdulrahman Alhabsi
Plants employ sophisticated molecular machineries to fine-tune their responses to growth, developmental, and stress cues. Plants cellular response influences gene expression through regulating processes like transcription and splicing. To increase the genome coding potential and further regulate the expression, pre-mRNA is alternatively spliced. Serine/Arginine-rich (SR) proteins, a family of pre-mRNA splicing factors, recognize splicing cis-elements and regulate both constitutive and alternative splicing. Recent studies reported only 22 SR proteins encoded in the genome of rice...

Targeted mutagenesis and functional analysis of CWC25 Splicing Factor in Rice via CRISPR/Cas9

Ahad M. Kababji
Pre-mRNA splicing is the most critical process in gene expression regulation across eukaryotic species. This reaction is carried out by the spliceosome, a large, dynamic, and well-organized ribonucleoprotein complex. The spliceosome is composed of five major small nuclear RNAs and an excessive number of associated protein factors. Many protein splicing factors bind and release during splicing to assist the assembly and the modulation of many RNA structures and proteins within the spliceosome. CWC25 is a...

Drag reduction by gas layers and streamlined air cavities attached to free-falling spheres

Aditya Jetly
The general objective of this thesis is to conduct experiments on sphere free-falling in liquid that advance our understanding of the drag reduction on solids moving in liquid by means of lubricating gas layers and attached streamlined air cavities. Part I of the thesis investigates the effect of thin air layers, naturally sustained on superhydrophobic surfaces, on the terminal velocity and drag force of metallic spheres free- falling in water. The surface of 20 mm...

In situ Investigation of the Effect of Solvation State of Lead Iodide and the Influence of Different Cations and Halides on the Two-Step Hybrid Perovskite Solar Cells Formation

Dounya Barrit
Perovskite solar cells have garnered significant interest thanks to the impressive rise of their efficiency over the last few years to a power conversion efficiency (PCE) of 25.2% despite being processable using cheap and potentially high-throughput solution coating techniques. Using the two-step conversion process high-quality perovskite films with high quality and uniformity can be produced, however, this process still needs a deeper and fundamental understanding. This thesis has shed light on the ink-to-solid conversion during...

Spectroscopy of Charge-Transfer States in Non-fullerene Acceptor Organic Solar Cells

Wejdan Alsufyani
The performance of non-fullerene acceptor (NFA)- based organic solar cells (OSC) has shown continuous increase in recent years, reaching power-conversion efficiencies up to 17% through the design and synthesis of efficient acceptor materials. Recent research is directed towards achieving higher efficiency of OSC, which is limited by the open-circuit voltage (Voc) which is lower than the Voc values achieved in inorganic or perovskites solar cells with comparable bandgaps. In this work, voltage losses in NFA...

Towards Supported Nitrogen Containing Fragments on Silica Surface for Catalytic Applications

Maha A. Aljuhani
This thesis shed lights on metal-nitrogen organometallic fragments supported on silica surface for catalytic applications. It Focuses on group IV and V metal transition as a well-defined single-site catalysts, specifically titanium, hafnium, and tantalum to utilize them in the development of selective heterogeneous catalysis for imine metathesis, hydroamination and hydroaminoalkylation of olefins and alkynes. Developing new metal-nitrogen containing fragments by using easily available and abundant precursors which is silica SiO2 and metal amides complexes. Here,...

Interactive High-Quality Visualization of Large-Scale Particle Data

Mohamed Ibrahim
Large-scale particle data sets, such as those computed in molecular dynamics (MD) simulations, are crucial to investigating important processes in physics and thermodynamics. The simulated atoms are usually visualized as hard spheres with Phong shading, where individual particles can be perceived well in close-up views. However, for large-scale simulations with millions of particles, the visualization of large fields-of-view usually suffers from strong aliasing artifacts, because the mismatch between data size and output resolution leads to...

Design and Fabrication of Multi-functional Photovoltaic-Membrane Distillation-Evaporative Crystallizer for Water Desalination, Electricity Generation, Salt Crystallization and Solar Cell Cooling

Sara Aleid
Ensuring electricity availability and acquiring access of potable water during emergencies in remote areas are becoming a global challenge around the world. Utilizing solar energy electricity generation by photovoltaics and clean water production by solar distillation have shown its great potential to meet the world’s future energy and water demands. In this work, we fabricated a photovoltaic-membrane distillation-evaporative crystallizer device (PV-MD-EC), in which high electricity generation efficiency (~15%), clean water production rate (~2.66 kg/m2 h)...

Unsupervised Method for Disease Named Entity Recognition

Abeer N. Almutairi
Diseases take a central role in biomedical research; many studies aim to enable access to disease information, by designing named entity recognition models to make use of the available information. Disease recognition is a problem that has been tackled by various approaches of which the most famous are the lexical and supervised approaches. However, the aforementioned approaches have many drawbacks as their performance is affected by the amount of human-annotated data set available. Moreover, lexicalapproachescannotdistinguishbetweenrealmentionsofdiseasesand...

Similarity Algorithms for Embeddable Objects

Anas Ismail
The need to measure similarity between two objects is everywhere. It is not always clear what it means for two objects to be similar. The definition changes depending on the area of application. However, similarity between two objects is generally defined as an inverse function to the distance between them. Also it is not always easy to apply distance functions on objects directly. Sometimes, we have to transform them or embed them in another space...

Spectro-Electrochemical Study of Staging in Graphitic Electrodes for Aluminum Batteries

Shianlin Wee
After three decades of commercialization, graphite remains the preferred active material for intercalation-type Li-ion battery anodes. Still, the characterization of staging continues to be elusive at the sub-micro- and nano-scales, the typical dimensions of graphite crystallites. Here, the intercalation of Al-based anions in graphitic materials was studied using X-ray powder diffraction (XRD) and Raman spectroscopy. While, in the first case, the analysis was done ex-situ and in mm3-samples, a more localized view was provided by...

Additively Manufactured Conformal Microwave Sensors for Applications in Oil Industry

Muhammad Akram Karimi
Depleting oil reserves and fluctuating oil prices have necessitated to increase the efficiency of oil production process. This thesis is focused on developing low-cost sensors, which can increase oil production efficiency through real-time monitoring of oil wells and help in safe transport of oil products from the wells to the refineries. Produced fluid from an oil well is a complex mixture of oil, water and gases, which needs to be quantified for various strategic and...

Design and evaluation of hybrid plasmonic nanostructures towards materialization of SERS sensors

Phuong Hoang
Optical sensors based on Surface-enhanced Raman scattering (SERS) effect are among the most versatile sensors due to their ability to characterize samples in various states of matter. The appeal of the SERS sensors lies in the molecular “fingerprint” specificity, sensitivity, and the non-invasive nature of the analysis. Although the current state of art SERS sensors have advanced toward ultrasensitivity with single-molecule detection limit, ultrafast analysis at femtosecond and sub-nanometer resolution, the application of these innovations...

Novel Surface Wave Imaging Methods

Zhaolun Liu
I develop four novel surface-wave inversion and migration methods for reconstructing the low- and high-wavenumber components of the near-surface S-wave velocity models. 1. 3D Wave Equation Dispersion Inversion. To invert for the 3D background S-wave velocity model (low-wavenumber component), I first propose the 3D wave-equation dispersion inversion (WD) of surface waves. The results from the synthetic and field data examples show a noticeable improvement in the accuracy of the 3D tomogram compared to 2D tomographic...

Supervirtual Interferometry and Seismic Imaging of the Oludvai Gorge, Tanzania

Kai Lu
This dissertation presents three novel applications of supervirtual interferometry (SVI) to seismic data: 3D refraction SVI, reflection SVI, and the combination of machine learning and SVI for automatic picking of SVI arrival times. The most important scientific finding of this dissertation is that I applied refraction SVI to seismic data recorded over the Olduvai Basin, Tanzania to more than double the source-receiver offset of pickable refraction arrivals. This allows us, for the first time, to...

Data for : Poly(A) Dataset for PAS sequences and pseudo-PAS sequences Classification (fasta format)

Fahad Albalawi, Abderrazak Chahid, Xingang Guo, Somayah Albaradei, Arturo Magana-Mora, Boris R. Jankovic, Mahmut Uludag, Christophe Van Neste, Magbubah Essack, Taous-Meriem Laleg-Kirati & Vladimir B. Bajic
This Dataset contains DNA sequences of the human genome hg38 from GENCODE folder at EBI ftp server (ftp://ftp.ebi.ac.uk/pub/databases/gencode/Gencode_human/release_28/GRCh38.primary_assembly.genome.fa.gz) A-Positive set (PAS sequences) Using GENCODE annotation for poly(A) (ftp://ftp.ebi.ac.uk/pub/databases/gencode/Gencode_human/release_28/gencode.v28.polyAs.gff3.gz) We selected poly(A) signal annotation. Using bedtools-slop option, we found regions extended 300 bp upstream and 300 bp downstream of the poly(A) hexamer. With the bedtools-getfasta option, we extracted 606 bp fasta sequences from these regions. After eliminating duplicates, we obtained 37’516 presumed true functional poly(A) signal...

Identification of MALAT1 as a PRC2-Ezh1 Associated lncRNA Essential for Epigenetic Control of Skeletal Muscle Adaptation and Plasticity

Nadine H. El Said
Polycomb Proteins (PcG) are chromatin proteins that control the maintenance of “transcriptional memory” and cell identity by fixing the repressed state of developmentally regulated genes. This function has been linked to interaction with RNA moieties, in particular long non-coding RNAs (lncRNAs). However, specificity of PcG-RNA interactions has been controversial (Beltran et al., 2016; Chen Davidovich, Leon Zheng, Karen J. Goodrich, & Thomas R. Cech, 2013). In this study we took advantage of recent work published...

Designing Surfaces for Enhanced Water Condensation and Evaporation

Yong Jin
With the increasing pressure of providing reliable potable water in a sustainable way, it is important to understand water phase change phenomena (condensation and evaporation) as the water phase change is involved in many processes such as membrane distillation and solar still which can be a feasible choice of supplementing the present potable water access. In the present thesis, we first elucidate the role of wettability of water condensation substrate by combining the droplet growth...

Facade Segmentation in the Wild

Wamiq Reyaz Para
Facade parsing is a fundamental problem in urban modeling that forms the back- bone of a variety of tasks including procedural modeling, architectural analysis, urban reconstruction and quite often relies on semantic segmentation as the first step. With the shift to deep learning based approaches, existing small-scale datasets are the bot- tleneck for making further progress in fa ̧cade segmentation and consequently fa ̧cade parsing. In this thesis, we propose a new fa ̧cade image...

Simultaneous Lightwave Information and Power Transfer (SLIPT)

José Ilton De Oliveira Filho
Harvesting energy became one of the most prominent research topics around the world, not only for research institutes and universities but also for technology companies as well. Mainly focused on internet of things (IoT) applications, harvesting energy is a crucial factor for reducing costs that come with the use of batteries and increasing the devices’ working time. Simultaneous lightwave information and power transfer is a technique that seeks to use wireless optical communication to achieve...

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