To meet the regulations on the emission of toxic gases such as Carbon Monoxide (CO) and Hydrogen Sulfide (H2S) from the Sulphur Recovery Units (SRUs), a high amount of fuel gas is burnt in the incinerator to oxidize them that increases the cost and CO2 emissions. BTEX are often present in the feed gas to SRU and failure to oxidize them in the furnace leads to increased emissions of toxic gases. This study investigates the role of oxygen enrichment on the emissions of CO and BTEX. The SRU simulations were conducted using plant data and a reaction mechanism. The results showed that oxygen enrichment could trigger the oxidation of BTEX and CO by the abundant SO and SO2 species in the furnace, thus assisting to decrease the emission of CO and BTEX from the furnace. This simulation results will assist in optimization of oxygen enrichment in SRU to reduce emissions.
In this research paper, we describe the design, model and test a soft-bodied, bioinspired, underwater robot that can potentially provide manipulation, locomotion and intervention in unstructured marine ecosystems and underwater industrial installations. The main innovative component of the robotic system is a flagellum-inspired elastic propulsor, composed of an electric motor connected to a propelling filament using a curved hook structure. The propulsor is capable of passively attaining a range of stable helical waves along its length due to interaction by its surrounding fluid and creating positive net thrust. This novel design provides a safe, robust and adaptable alternative to traditional rigid propellers while being suitable for locomotion as well as manipulation tasks. The complete robotics system will be equipped with high-resolution cameras and underwater sensors to achieve a safe and reliable interaction with the environment, including ship and submarine hulls, and offshore oil/gas pipeline. We investigate the relationship between actuation velocity and material elasticity, as well as the instantaneous and angular velocity of a single flagellated canister in a self-propelled test.
Machine learning-based approach is desired for accelerating materials design, development and discovery. Bayesian optimization, a trending machine learning technique, is attracting growing attention in materials science. As a first attempt to date, we propose to apply Bayesian optimization to design ultrathin multilayer spectrally selective absorber coatings for hightemperature solar power generation. The optimized design of a trilayer W-SiC nanocomposite coating achieves a total solar absorptance over 92.9% in the wide wavelength range of 250? 1750 nm. Our subsequent fabrication and experimental characterization have demonstrated the capability of the proposed approach. This closed-loop machine-learning-based approach sheds light on the autonomous discovery of materials for solar energy and sustainability applications.
As Silicon-based power devices are reaching their theoretical limit, wider bandgap materials like GaN and SiC have become the main focus for power applications, owing to their superior electrical properties such as high critical electric field and saturation drift velocity. In practice, effective edge terminations techniques, such as junction termination extension (JTE) structures, play a crucial role in realizing high-voltage devices. Though certain challenges in fabricating such devices, such as difficulty in forming p-type region in GaN, makes it difficult to realize edge termination, hence impeding the development and adoption of such devices. This work reviews the available techniques to realize such edge termination and discuss their limitations and the techniques used to overcome the shortcomings in fabricating such devices.
The problem of Simultaneous Localization and Mapping (SLAM) approaches has been under investigation over the past few decades and different approaches are present in the literature, targeting efficiency, robustness, scalability, or reliability. Semantic SLAM is currently attracting researchers in the robotics field and several operable solutions are developed, yet, the problem of corrupted visual measurements under challenging environmental conditions remains unsolved. In this work, we will develop an online Semantic SLAM system that is robust against object occlusions; one of the most significant error sources that may hinder the robustness of Semantic SLAM. The proposed approach will be evaluated in simulations to prove its validity.
It is widely known that fluid flow exhibits different flow characteristics at different scales. This is true especially for the porous rocks which are mostly heterogenous and can have pores of different sizes ranging from 103-10-8 m. This work consists of characterization of petrol-physical properties of porous media at different scales. The two properties which play an important role in characterization of rock samples are absolute permeability and relative permeability. Using cutting edge technology of Digital Rock Physics (DRP) we characterize single phase and multiphase properties of Silurian Dolomite rocks. 3D scans of rock were taken at four different image resolutions i.e. 39.93 um, 13.24um, 5.32 um and 0.64 um. We perform numerical modeling for single phase flow at different size images and find Representative Element Volume (REV) for absolute permeability. Similarly, we perform numerical modeling using Pore Network Model (PNM) for multiphase flow and characterize relative permeability at different scales.
Hydrotreatment is the industrial process used to achieve low sulfur and nitrogen concentrations in fuels. However, it is conducted at severe conditions, which makes it an expensive and energy intensive process. Aiming to reduce the energy consumption of hydrotreatment, liquid? liquid extraction is considered as a pre-treatment. In this work, the mixtures of pyridine/n-octane and benzothiazole/n-octane were selected as an oil models and two deep eutectic solvents (DES) were evaluated for their pyridine extractive ability. For this purpose, the liquid-liquid equilibria (LLE) of these DES systems have been determined at 298 K and 1.01 bar. Also, the distribution ratios and the selectivities were calculated from the experimental LLE data. The selected DESs were: (i) methyltriphenyl phosphonium bromide/ethylene glycol with molar ratio of 1:4 (DES 1) and (ii) methyltriphenyl phosphonium bromide/glycerol with molar ratio of 1:4 (DES 2). Finally, both DESs were found to be promising denitrogenation and desulfurization agents.
Compared to open heart surgeries, minimally invasive cardiac surgeries (MICS) are currently performed to minimize surgical trauma, reduce post-surgical adverse complications and fasten recovery. MICS are performed by steering a flexible catheter inside blood vessels and heart chambers. Surgeons mainly rely on x-ray images to manipulate catheters inside the beating heart. However, MICS clinical challenges include difficulty in maneuvering the catheter through the curved blood vessels, errors in positioning the catheter within the beating heart and inability to apply optimal contact force with the cardiac wall. An example for MICS is cardiac ablation, which is performed to treat drug resistive arrhythmia patients. The success rate of the procedure depends on the ability of the catheter to remain in constant contact with the cardiac wall. Several robotic systems have been developed for use in MICS to increase the precision and dexterity of the surgical procedures; however, the rigidity of conventional link-joint robots increases the risk of injuries. In this project, we propose a concentric tube robot design, which is highly flexible and can maintain consistent contact with the moving cardiac wall, through force and stiffness control. Mathematical modelling of the robotic catheter is illustrated to prove design feasibility.
This paper shows a study of a three-dimensional transient flow around a road bicycle that was designed in Khalifa University. This study is done using the commercial code ANSYS? Fluent at a speed of 16.67 m/s using SST k-? model. This study will be considered as a baseline reference for future aerodynamics improvements. The discussed results are drag, lift, velocity magnitude, and total pressure.
Ionic liquids have been widely identified by their negligible vapor pressure, thermal stability and wide electrochemical window, when compared to conventional organic solvents. These characteristics enabled them to take part in many water treatment processes such as the extraction of organic and inorganic pollutants. In this work, boron solubility was measured in four different hydrophobic ionic liquids, namely, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-methyl-1propylpiperidinium bis(trifluoromethylsulfonyl)imide, 1-Propyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, and Octyl-triethylammonium bis(trifluoromethylsulfonyl)imide at different temperatures from 25? to 85 ?C. The results showed that at 25?C concentration of boron, in the form of boric acid, was highest in imidazolium-based IL (204.4 ppm), and lowest in the ammonium-based one (27.5 ppm). This shows the important effect of the structure of the cation of ionic liquids on their physical behavior since the anion is the same in the four studied ionic liquids. A steep increase in the solubility was observed for all ILs at 85?C. Furthermore, the increasing solubility with temperature showed an exponential relationship for all ILs. These finding lay the ground for further applications of ILs in pretreatment of seawater.
