Rotordynamic and Erosion Study of Bearings in Electrical Submersible Pumps

Electrical Submersible Pumps (ESPs) are widely used for oil production. Reliability studies of ESPs are important to increase their life span, thus improving profits. Experimental data of a 185-hour erosion on a WJE-1000 ESP has been analyzed. The eroded bearings are inspected in micron scale with a certain time interval. It shows that bearings and seals in the ESPs are the main factors causing vibrations and failure of the ESP systems. To better understand the rotordynamic behavior and material fatigue of the bearings/seals in ESPs, a vertical bearing/seal test rig is built. The test rig simulates the motion of rotating components in a WJE-1000 ESP and conducts multi-phase erosion experiments efficiently with water, air and sand. Experiments on plain journal bearings with different radial clearances, mass imbalances, and multi-phase flows are conducted using the bearing/seal test rig. Computational Fluid Dynamics (CFD) simulations are performed to study the fluid zone in the journal bearings. A Fluid Structure Interaction (FSI) simulation based on Fluent and MATLAB is proposed. It predicts the transient motions of the rotor-bearing system, which provides essential information needed for the design of rotor-bearing systems. In addition, an optimized FSI simulation using pre-built bearing model and Timoshenko beam model is proposed to improve the time efficiency of the FSI simulation further. This study provides an efficient way to study the bearings/seals in the field of rotordynamics and material, which is important for the reliability study of ESPs. Meanwhile, the FSI simulations predict the transient behaviors of the rotor-bearing system, providing important reference for the design and modification of bearings/seals

Rotordynamic and Erosion Study of Bearings in Electrical Submersible Pumps

Electrical Submersible Pumps (ESPs) are widely used for oil production. Reliability studies of ESPs are important to increase their life span, thus improving profits. Experimental data of a 185-hour erosion on a WJE-1000 ESP has been analyzed. The eroded bearings are inspected in micron scale with a certain time interval. It shows that bearings and seals in the ESPs are the main factors causing vibrations and failure of the ESP systems. To better understand the rotordynamic behavior and material fatigue of the bearings/seals in ESPs, a vertical bearing/seal test rig is built. The test rig simulates the motion of rotating components in a WJE-1000 ESP and conducts multi-phase erosion experiments efficiently with water, air and sand. Experiments on plain journal bearings with different radial clearances, mass imbalances, and multi-phase flows are conducted using the bearing/seal test rig. Computational Fluid Dynamics (CFD) simulations are performed to study the fluid zone in the journal bearings. A Fluid Structure Interaction (FSI) simulation based on Fluent and MATLAB is proposed. It predicts the transient motions of the rotor-bearing system, which provides essential information needed for the design of rotor-bearing systems. In addition, an optimized FSI simulation using pre-built bearing model and Timoshenko beam model is proposed to improve the time efficiency of the FSI simulation further. This study provides an efficient way to study the bearings/seals in the field of rotordynamics and material, which is important for the reliability study of ESPs. Meanwhile, the FSI simulations predict the transient behaviors of the rotor-bearing system, providing important reference for the design and modification of bearings/seals

Unbound

For many years, I have been repeatedly trying to understand what the term “trauma” means to me. While invisible, my trauma is ever-present, and I have not been able to understand how it has trapped me and my inner feelings. At the same time, more recently I don’t feel helpless or abandoned. I have been trying to tap the potential of connecting with the world outside, thereby piecing together the broken bits and pieces and reconciling with my family, past sorrows and myself. In my thesis collection, I pay homage to a garden I often visited as a child. The garden was a refuge, a place where I felt safe and free. My garments depict and interpret elements of that garden in a wide range of applications, from felted fringe to printed silk. They play with varied forms of camouflage, protection, and reclamation. These garments recall memories and hardships that I experienced growing up as well as places where I found extreme warmth and comfort that helped me get through it all. They are meant to be wearable and in being worn, offer solace to all who may be stuck in a dark world and hoping to find peace and freedom someday

THE RELATIONSHIP BETWEEN NURSING STUDENTS’ TRANSFORMATIONAL LEADERSHIP STYLE AND THEIR SELF-REGULATION IN ASSUMPTION UNIVERSITY IN THAILAND

This study aimed to investigate the relationship between Transformational Leadership and Self-Regulation based on nursing students' perceptions at Assumption University, Bangkok, Thailand. This study was conducted with 72 nursing students in the academic year 2020 – 2021. Three main objectives were included in this study. The first objective was to determine the level of nursing students’ Transformational Leadership Style. The second objective was to determine the level of nursing students’ Self-Regulation. The third objective was to determine if there is a relationship between nursing students' Transformational Leadership Style and their Self-Regulation at Assumption University. The findings showed that the perceptions of nursing students toward Transformational Leadership presented at a high level, and the perceptions of nursing students towards Self-Regulation presented at a moderate level. The results demonstrated a moderate positive correlation, for the (r) value was .495** at the significant level of 0.000, which was less than 0.05 level, in the perceptions of nursing students

Discovery of (E)-3-(4-(Diethylamino) phenyl)-1-phenyl-2-phenylsulfonyl)prop-2-en-1-one as Novel Cannabinoid Receptor 2 Ligands

Cannabinoids (CB) are defined as a class of compounds that can act on Cannabinoid receptors 1 or 2 (CB1 or CB2) and affect human physiology. Both CB1 and CB2 receptors belong to the rhodopsin-like family of G-Protein Coupled Receptors (GPCRs). However, CB1 receptor is mainly expressed in the central nervous system, while CB2 receptor is dominantly located in the peripheral nervous system and immune cells. By now, scientists have discovered many CB ligands that have therapeutic potentials, but the limitation of non-selective ligands is the psychiatric side effect mediated by the activation of CB1 receptor. Although CB1 receptor is crucial in analgesic and anti-inflammatory effects, strategies of designing CB2 selective ligands are made by medicinal chemists to avoid undesirable effects in clinic. In this thesis, we discovered novel CB2 lead compounds with new chemical scaffolds; designed and synthesized four series of analogues for the structure-activity relationship (SAR) studies; tested their binding affinity to both CB2 and CB1 receptors; conducted in-vitro functional studies; and evaluated their potentials for therapeutic treatment. In total, four series of (E)-3-(4-Ethoxy-3-methoxyphenyl)-2-((4-methoxyphenyl) sulfonyl)-1-phenylprop-2-en-1-one have been identified as novel cannabinoid ligands. Physicochemical properties were predicted and docking studies using our CB2 model was conducted. 29 derivatives were then synthesized to conduct SAR studies. The binding affinity and selectivity for cannabinoid receptor CB1 and CB2 were then evaluated. Four compounds showed high CB2 binding affinity (Ki of 10-60 nM) and good selectivity (CB1/CB2 of 20- to 1305 fold). Their off-targets effects were also predicted. Overall, these sulfone derivatives can be used to develop novel therapeutic CB2 ligands

Crystal Structure of the S. solfataricus Archaeal Exosome Reveals Conformational Flexibility in the RNA-Binding Ring

The exosome complex is an essential RNA 3'-end processing and degradation machinery. In archaeal organisms, the exosome consists of a catalytic ring and an RNA-binding ring, both of which were previously reported to assume three-fold symmetry.Here we report an asymmetric 2.9 A Sulfolobus solfataricus archaeal exosome structure in which the three-fold symmetry is broken due to combined rigid body and thermal motions mainly within the RNA-binding ring. Since increased conformational flexibility was also observed in the RNA-binding ring of the related bacterial PNPase, we speculate that this may reflect an evolutionarily conserved mechanism to accommodate diverse RNA substrates for degradation.This study clearly shows the dynamic structures within the RNA-binding domains, which provides additional insights on mechanism of asymmetric RNA binding and processing

Automatic arc discharge-induced helical long period fiber gratings and its sensing applications

We experimentally demonstrate an automatic arc discharge technology for inscribing high-quality helically twisted long period fiber gratings (H-LPFGs) with greatly improved inscription efficiency for single mode fibers. The proposed technology has been developed by implementing an embedded program in a commercial fusion splicer, which employs an ultraprecision motorized translation stage while the tensioning mass required by conventional inscribing technology is eliminated. More significantly, the arc-induced H-LPFGs have been reported to have potential usage as sensors in temperature, refractive index, twist stress, and strain