Below are recent articles (co-)authored by Brunel academic staff. Please click the title of the article to access the full-text.
Monocular spatial geometrical measurement method based on local geometric elements associated with out-of-view datum
Liu, F. et al
Measurement, Vol 214, Art No. 11282 (Jun 2023)
In the field of industrial inspection, visual non-contact measurement of the radial dimension of the extension end of the long pole structure is a difficult problem. Utilizing the principle of telecentric vision measurement, we propose a monocular spatial geometrical measurement method based on local geometric elements associated with out-of-view datum, focusing on key techniques such as visual calibration and global unification of separate dimensions. Firstly, the designed associated target is used to establish the conversion relationship between the measurement reference space and the camera FOV space. Singular Value Decomposition (SVD) is used to obtain the initial values R0 and T0 of the rotation matrix and translation vector during the three-dimensional coordinate system conversion...
Surface-temperature-induced Marangoni effects on developing buoyancy-driven flow
Wissink, J. G. et al
Journal of fluid mechanics, Vol 962, Art No. A23; PII S002211202300263X (May 2023)
To investigate the initial development of the Rayleigh-Benard-Marangoni (RBM) instability in a relatively deep domain, direct numerical simulations for a large range of Marangoni and Rayleigh numbers were performed. In the simulations, the surface was assumed to be flat and surface cooling was modelled by a constant heat flux. The small-scale dynamics of the flow and temperature fields near the surface was fully resolved by using a non-uniform vertical grid distribution. A detailed investigation of the differences in physical mechanisms that drive the Rayleigh-and Marangoni-dominated instabilities is presented. To this end, various properties such as the maturation rate of convection cells, the fluctuating kinetic energy and the surface characteristic length scale were studied. It was confirmed that buoyancy forces and surface-temperature-gradient-driven Marangoni forces enhance one another in promoting the development of the RBM instability. When using a relevant measure of the effective thermal boundary layer thickness as length scale, both the critical Marangoni and Rayleigh numbers, obtained for the purely Marangoni-and purely Rayleigh-driven instabilities, were found to be in good agreement with the literature.
Thermal efficiency and specific work optimization of combined Brayton and inverse Brayton cycle: A multi-objective approach
Prajapati, P. et al
Thermal science and engineering progress, Vol 37, Art No. 101624
The multi-objective optimization study of the combined Brayton and inverse Brayton cycle is carried out with the aim to maximize specific work output and minimize thermal efficiency using an evolutionary heat transfer search optimization algorithm. The design variation considers the top cycle pressure ratio and bottom cycle expansion pressure. From the results of the multi-objective optimization, multiple optimal solutions for the objective functions are presented using a Pareto optimal curve...
The performance of millimeter-wave over fiber using electro absorption modulator and avalenche photodiode
Al-Wahaibi, F. et al
Optik, Vol 273, Feb 2023
In this paper, a parallel MZM and a quadrupling frequency technique are used to produce a 72 GHz mm-wave. The determined optical sideband suppression ratio (OSSR) is 71 decibels. This mm-wave signal's performance is compared to that of two optical modulators, the Mach Zehnder Modulator (MZM) and the Electro Absorption Modulator (EAM) as well as two different kinds of photodiodes, the Avalanche Photodiode (APD) and the PIN-PD...
Diesel Spray Liquid Length Imaging at High Pressure
Sphicas, Panos et al
Energies, Vol 16, No 6, Art 2874 (Mar 2023)
Engine efficiency and emissions depend on the fuel atomization and dispersion. The fuel atomization and dispersion depend heavily on the ambient pressure and temperature. In this work, to study Diesel sprays in engine conditions, an electrically heated, constant-volume, pressurized vessel was designed and manufactured. The controlling electronics and software were developed and tested to ensure safe and precise operation. A commercial Bosch six-hole automotive Diesel injector was used...
Sequence-to-Sequence Change-Point Detection in Single-Particle Trajectories via Recurrent Neural Network for Measuring Self-Diffusion
Martinez, Q. et al
A recurrent neural network is developed for segmenting between anomalous and normal diffusion in single-particle trajectories. Accurate segmentation infers a distinct change point that is used to approximate an Einstein linear regime in the mean-squared displacement curve via the transition density function, a unique physical descriptor for short-lived and delayed transiency. Through several artificial and simulated scenarios, we demonstrate the compelling accuracy of our model for dissecting linear and nonlinear behaviour.
A Comparison of Two Types of Acoustic Emission Sensors for the Characterization of Hydrogen-Induced Cracking
Sensors (Basel, Switzerland), Vol 23, No 6, (Mar 2023)
In this study, two commonly used AE sensors (Nano30 and VS150-RIC) were used for monitoring HIC processes using the electrochemical hydrogen-charging method under laboratory conditions. Obtained signals were analyzed and compared on three aspects, i.e., in signal acquisition, signal discrimination, and source location to demonstrate the influences of the two types of AE sensors...