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.
This paper explores the potential of using the Sheet-based Gyroid TPMS structure as a potential heat sink design. The use of selective laser sintering as a fabrication method is investigated through assessing the accuracy of the printed samples to the designed samples. Scanning electron microscopy and micro-computed tomography are employed to visualize the external and internal microstructure of the printed samples. It is found that there is an inverse relation between the number of defects in a sample and its relative density.
Backward whirl vibration amplitude of rotary system is an important characteristic for early rotor failure detection which otherwise could lead to a serious environmental, health and safety implications. In order to minimize such consequences, an effort was pledged by many researches to study and simulate dynamic response of cracked rotor with breathing crack function for any such characteristics as Backward Whirl phenomena. Nevertheless, current studies presented in the literature have not addressed the transition from forward to backward whirl orbits at the critical backward whirl rotational speeds as a potential indicator for crack presence that can be used for early damage detection. Past numerical and theoretical studies/evaluation showed that the propagation of the fatigue/open crack in rotor systems could excite backward whirl orbits during passages through critical backward whirl rotational speeds. These backward whirl orbits cannot be theoretically excited in crack-free rotors, which make them a unique signature for crack detection in rotors. In the present work, it was proven that backward whirl can be captured using simple 2-DOF Jeffcott Rotor simulation with breathing crack at various crack depth and unbalance orientation angles with respect to transverse crack direction.
Nonlinear Energy Sinks (NESs) are local attachments used to rapidly and passively dissipate energy from a primary structure in a phenomenon known as Targeted Energy Transfer (TET). Single-Sided Vibro-Impact (SSVI) NESs are one type where impacts, usually between the top floor of the primary system and the NES, are utilized to further dissipate energy. In literature, researchers have mostly considered steel-to-steel impacts which mean a coefficient of restitution of approximately 0.7. In this work, the effect of changing this coefficient of restitution will be analyzed and investigated in a 2 Degree-Of-Freedom (DOF) physical primary structure which leads to significant enhancement in energy transfer and dissipation.
Dry reforming of methane (DRM) offers a greener source of energy. However, the Ni based catalysts used in this endothermic process suffer from coking and sintering. This paper explores nano-catalysts that can be used in this reaction obtained by a top-down and bottomup techniques. CoPt bimetallic nanocolloidal particles were synthesized via polyol method, while zeolite Y (CBV720) ball-milled. Electron microscopy and XRD were utilized to characterize the samples obtained. Results showed that monodispersed metal nanoparticles were obtained. Conversely, ball milling did not achieve nanosized particles.
