The last decade’s studies show that the PoL (point-of-load) converter’s output capacitor is an important component for reliability, implying that its careful selection may determine the overall converter’s failure rate and lifetime. PoL converters are commonly found in many electronic systems, usually as part of the Intermediate Bus Architecture (IBA). Their important requirements are a stable output voltage at load current variation, good temperature stability, a low output ripple voltage, high efficiency, and reliability. If the electronic system is portable, a small footprint and low volume ..read more

Direct-drive permanent magnet machines are ideal candidates for remote renewable applications, due to their independence from gearboxes and minimization of maintenance needs. However, faults may still appear in the generator of such a machine and affect its operation and production. Not only can demagnetization cause a catastrophic breakdown if left unchecked, but it also directly impacts the output quality of generators. As such, demagnetization is a topic of great interest. This paper investigated the sensitivity of three diagnostic methods—current signature analysis (CSA), Park’s vector app ..read more

Environment control systems in broiler houses utilize non-renewable electricity and fuels as energy sources, contributing to the increase in greenhouse gases, while not providing optimal conditions. The heat pump (HP) is an energy-efficient technology that can continuously regulate the indoor temperature and relative humidity by combining different operation modes (heating, cooling, and dehumidifying). The current study presents an analytical numerical model developed in Simulink, capable of simulating the thermal loads of a broiler house and the dynamic operation of three heat pumps to cover ..read more

Sustained casing pressure (SCP) is a common problem during an entire life span of oil and gas wells. When conventional methods are deployed to resolve the issue, the methods seem to have some setbacks by being unable to seal microcracks in the wellbores. A new solid-free resin sealant was developed by increasing the amount of active hydrogen in the curing agent. This low-temperature cure results in low viscosity, excellent mechanical properties, and chemical stability. The experimental results show that the resin sealant can be used at temperatures ranging from 20 to 50 °C, and the curing time ..read more

Coiled tubing (CT) is used as a velocity string to transport high-velocity gas in drainage gas recovery technology. Sand particles flowing at high speed can cause serious erosion of the pipe wall. Long-term erosion wear leads to the degradation of the string strength and can even cause local perforation. In order to study the erosion wear problem of CT, a gas–solid erosion experimental device was established for a full-size pipe with different radii of curvature. A 3D laser confocal technique was used to examine and characterize the microscopic erosion morphology of the inner wall of the CT. T ..read more

Studying a large number of scenarios is necessary to consider the uncertainty inherent to the energy transition. In addition, the integration of intermittent renewable energy sources requires complex energy system models. Typical days clustering is a commonly used technique to ensure the computational tractability of energy system optimisation models, while keeping an hourly time step. Its capability to accurately approximate the full-year time series with a reduced number of days has been demonstrated (i.e., evaluation). However, its impact on the results of the energy system model (i.e., eva ..read more

This study addresses heat and mass transfer of electrical magnetohydrodynamics (MHD) Williamson fluid flow over the moving sheet. The mathematical model for the considered flow phenomenon is expressed in a set of partial differential equations. Later, linear and nonlinear ordinary differential equations (ODEs) are obtained. The finite element method tackles a reduced system of ODEs with boundary conditions. Galerkin weighted residuals and constructs of weak formulations constitute the basis of this method. An iterative procedure is considered for handling nonlinear terms in a given system of O ..read more

Safe drilling and effective fracturing are constant challenges for shale formations. One of the most important influencing factors is the accurate characterization of the deformation and damage caused by inherent lamination and natural fractures. Furthermore, shale formations exhibit fine-scale heterogeneity, which conventional laboratory methods (linear variable differential transformer (LVDT), strain gauges, etc.) cannot distinguish. To overcome these constraints, this research aims to investigate the damage and deformation characteristics of shale samples using three-dimensional digital ima ..read more

Over the three-day gasification test of a large coal block with oxygen in atmospheric pressure conditions, the yield and composition of the tar collected was investigated. The tar was sampled approximately every 7 h into sorption tubes directly from the reactor outlet. Sand, with a moisture content of 11%, was used as an insulating material to simulate the environment of the gasified coal seam. Light aromatic hydrocarbons (BTEX), phenols, and polycyclic aromatic hydrocarbons (PAHs) were determined in the tar. The results that were obtained were recalculated into the concentrations of the indiv ..read more

In this work, the solar-thermal-chemical integrated design for a methane dry reforming reactor with cavity-type solar absorption was numerically performed. Combined with a multiphysical reactor model, the gradient optimization algorithm was used to find optimal radiation flux distribution with fixed total incident solar energy for maximizing overall hydrogen yield, defined as the ratio of molar flow of exported hydrogen to imported methane, which can be applied for guiding the optical property design of solar adsorption surface. The comprehensive performances of the reactor under the condition ..read more