by Wilson C. Chin  , Xiaoying Zhuang  and Jamie A. Chin

Received: 07 September 2024;  Published: 06 December 2024;  doi: 10.21926/jept.2404023

Our new approach to MWD mud pulse telemetry offers significant increases over conventional data rates. Using waveguide acoustics, we show that common drilling communications channels support carrier frequencies exceeding several hundred Hertz. Such signals are prone to attenuation over large drillpipe distances. Low power, self-spinning “turbosirens” are designed, providing high torque and rotation rate performance at all flow rates without electric or hydraulic motor drives. The sirens rota [...]

by Rui Wang  , Omar M. Basha  , Husain E. Ashkanani  , Bingyun Li  and Badie I. Morsi

Received: 19 August 2024;  Published: 21 November 2024;  doi: 10.21926/jept.2404022

CO2 capture processes using five chemical solvents were modeled in Aspen Plus V.12.1 for the capture of more than 90% CO2 from a 456 ton/hour split flue gas stream containing 12.02 mol% CO2 emitted by the Longview 780 MW power plant (West Virginia, USA). Since the flue gas contained 33.10 ppmv SO2 and 35.47 ppmv NO2, a gas polishing process, using deionized water (DIW), was included in the model for complete scrubbing of SO2 and NO2 from the raw flue gas before the CO2 capture process. The five [...]

by Minyang Wang  , Daming Zhang  and Liang Yuan

Received: 15 July 2024;  Published: 15 November 2024;  doi: 10.21926/jept.2404021

As the penetration level of inverter-based generators continues to increase, it becomes crucial to reduce power oscillations between inverters and synchronous generators (SG) to improve system stability. This paper uses a multimachine system as the research platform and proposes a grid separation method employing a multi-terminal back-to-back converter. The converter is designed to be placed at the point of common coupling (PCC) in the original multimachine system and can divide the original gri [...]

by Marco Antonio Gaya de Figueiredo  , Luiza G. dos Santos  , Rômulo Luciano Nascimento  and Harrison Lourenço Corrêa

Received: 18 April 2024;  Published: 11 November 2024;  doi: 10.21926/jept.2404020

Hydrogen is crucial in various industrial sectors and can be obtained through different synthesis routes. However, a significant portion of its production still relies on chemical processes involving fossil fuels, resulting in hydrogen and the generation of greenhouse gases (GHGs) as the final byproduct. In alignment with the goals of the 2030 Agenda, where countries commit to implementing energy transition, hydrogen obtained through a green route has been increasingly explored by governmental a [...]

by Fatemeh Mollaamin

Received: 15 August 2024;  Published: 07 November 2024;  doi: 10.21926/jept.2404019

A comprehensive investigation on hydrogen grabbing by SiO-GeO was carried out, including DFT computations at the CAM-B3LYP-D3/6-311+G (d,p) level of theory. The data shows that if silicon elements are replaced by germanium, the H-grabbing energy will be ameliorated. Electromagnetic and thermodynamic properties of SiO, GeO, and SiO-GeO nanoclusters have been evaluated. The hypothesis of the hydrogen adsorption phenomenon was confirmed by density distributions of PDOS and LOL for hydrated nanoclus [...]

by Kwami Eli Baba  , Guy Pluvinage  and Julien Capelle

Received: 06 August 2024;  Published: 31 October 2024;  doi: 10.21926/jept.2404018

Ammonia is a toxic gas and can cause tragic consequences for humans. The damage level depends on concentration and duration of exposure. The security length associated with the risk of a tank leak at the acute exposure level of 30 ppm (AEGL-1) has been computed. Two tools have been combined: the CTOA criterion and the ALOHA software. The CTOA, a measure of fracture resistance against ductile crack propagation, is implemented in Abaqus software to compute the size of a breach in a tank submitted [...]