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"Ibrahim, Yusuf"
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Reliability analysis of a small solar system for a home
PurposeThe purpose of this paper is to model and to improve the stability and long-lasting operation of the small home solar system configuration regarding the reliability, availability, sensitivity, cost analysis and mean time to failure (MTTF).Design/methodology/approachA model of a small home solar system is designed in this write up. It is designed in a series–parallel configuration, such that four panels are arranged in parallel, working under 1-out-of-4: G; policy and two batteries configured in parallel also, working under 1-out-of-2: G; policy. The panels are connected to a charge controller, then to the batteries and lastly to an inverter, all connected together in series configuration. Different types of system reliability such as reliability, sensitivity, availability, MTTF and cost analysis for particular values of the failure and repair rates have been evaluated by using a supplementary variable and Laplace transforms and demonstrated the computed results on tables and graphs. The main objective here is to improve the stability and long-lasting operation of the small solar system configuration regarding the reliability, availability, sensitivity, cost analysis and MTTF.FindingsThe future behavior of the small solar system and similar systems can be easily predicted at any given time for any parametric values, it is also better to provide repair than replacements in the system for better availability and reliability, it signifies that γp, γb, γc and γi are responsible for the better performance of the system, the variation of sensitivity together with the parametric values variations and lastly deduced that the profit will decrease whenever service cost increase.Originality/valueThis paper provides a model of small home solar system and its reliability analysis.
Journal Article
Multifunctional Poly(Acrylic Acid)-Coated EuBiGd2O3 Nanocomposite as an Effective Contrast Agent in Spectral Photon Counting CT, MRI, and Fluorescence Imaging
Introduction: Recently, diagnostic methods based on multimodal and non-invasive imaging, such as MRI and CT scanners, have been developed for accurate cancer diagnosis. A key limitation of these imaging systems is their low contrast. Therefore, developing stable, non-toxic, and efficient multimodal imaging contrast agents is desirable. In this work, we demonstrated the synthesis of a poly(acrylic acid) (PAA) – coated nanoparticles (NPs), PAA@EuBiGd2O3-NPs as an imaging agent for contrast enhancement in spectral photon-counting computed tomography (SPCCT), magnetic resonance imaging (MRI) and fluorescence imaging (FL).Methods: We synthesized PAA-coated EuBiGd2O3-NPs using a polyol method by dissolving metal nitrates and PAA in triethylene glycol. NaOH solution was added under constant heating at 180°C. The nanoparticles were precipitated with the addition of ethanol, then washed, dried, calcined at 600°C, and redispersed in water for further studies. The nanoparticles were characterized using TEM, SEM, XRD, XPS, FTIR, and PL spectroscopy. PAA@EuBiGd2O3-NPs were tested in vitro for their cytocompatibility with lung cancer epithelial cells (A549). The nanocomposite image contrast enhancement was evaluated using SPCCT, MRI, and FL imaging.Results: The cell viability study showed that PAA@EuBiGd2O3-NPs is safe up to 250 μg/mL, exhibiting IC50 values of 365.8 and 337.8 μg/mL after 24 and 48 hours, respectively. The NPs have strong X-ray attenuation with a slope of ~61 HUmL/mg, as determined from the SPCCT concentration-dependent analysis. The MRI of the NPs reveals a high T1 contrast with a relaxivity of 11.77 mM− 1s− 1. Fluorescence imaging of cells incubated with PAA@EuBiGd2O₃-NPs shows strong red luminescence.Conclusion: The new nanocomposite has proven to be an effective trimodal contrast agent with high attenuation in CT, enhanced T1 signal in MRI, and strong red luminescence in FL imaging with promising diagnostic capabilities.
Journal Article
Crustal structure and seismic anisotropy of rift basins in Somaliland
Rift margins provide insights into the processes governing the rupture of the continental lithosphere and the subsequence formation of sedimentary basins. The Proterozoic basement underlying Somaliland has been affected by multiple rifting; however, the crustal structure of these rifted basins remains unknown. This study utilized teleseismic receiver function analysis, Bayesian inversion, common conversion point imaging and 2D forward gravity modelling to examine the crust and upper mantle of Somaliland. The results indicate 36.8–38.2 km of crust in southern Somaliland, while the central and northern regions feature thinned crust (~ 21 km) with 5–6 km thick sediments. The joint analysis of radial and transverse components of receiver functions and shear wave splitting revealed fast axis directions trending to 50–56° in the upper mantle, indicating that azimuthal anisotropy is oriented in the regional Africa-Arabia plate motion. Such orientation may have resulted from lattice preferred orientation of olivine from the asthenospheric flow. Additionally, the fast polarization of the crust in central Somaliland is oriented at − 15°, indicating fossil deformation in the thinned crust related to the NW–SE trending Late Jurassic rift event. Further, the fast polarization for stations near the Gulf of Aden is oriented at 75–80°, suggesting crustal deformation associated with the Oligocene rift event. The crustal anisotropy at southern Somaliland revealed fast polarization oriented at − 85°, indicating a preserved far-field response of the WNW-ESE trending Late Cretaceous rift event. Overall, the study provides for the first-time insight into the rift-related extensional strain fabric in the crust and upper mantle anisotropy induced by asthenospheric flow in Somaliland.
Journal Article
Reliability modeling and performance evaluation of solar photovoltaic system using Gumbel–Hougaard family copula
PurposeSolar photovoltaic (PV) is commonly used as a renewable energy source to provide electrical power to customers. This research establishes a method for testing the performance reliability of large grid-connected PV power systems. Solar PV can turn unrestricted amounts of sunlight into energy without releasing carbon dioxide or other contaminants into the atmosphere. Because of these advantages, large-scale solar PV generation has been increasingly incorporated into power grids to meet energy demand. The capability of the installation and the position of the PV are the most important considerations for a utility company when installing solar PV generation in their system. Because of the unpredictability of sunlight, the amount of solar penetration in a device is generally restricted by reliability constraints. PV power systems are made up of five PV modules, with three of them needing to be operational at the same time. In other words, three out of five. Then there is a charge controller and a battery bank with three batteries, two of which must be consecutively be in operation. i.e. two out of three. Inverter and two distributors, all of which were involved at the same time. i.e. two out of two. In order to evaluate real-world grid-connected PV networks, state enumeration is used. To measure the reliability of PV systems, a collection of reliability indices has been created. Furthermore, detailed sensitivity tests are carried out to examine the effect of various factors on the efficiency of PV power systems. Every module's test results on a realistic 10-kW PV system. To see how the model works in practice, many scenarios are considered. Tables and graphs are used to show the findings.Design/methodology/approachThe system of first-order differential equations is formulated and solved using Laplace transforms using regenerative point techniques. Several scenarios were examined to determine the impact of the model under consideration. The calculations were done with Maple 13 software.FindingsThe authors get availability, reliability, mean time to failure (MTTF), MTTF sensitivity and gain feature in this research. To measure the reliability of PV systems, a collection of reliability indices has been created. Furthermore, detailed sensitivity tests are carried out to examine the effect of various factors on the efficiency of PV power systems.Originality/valueThis is the authors' original copy of the paper. Because of the importance of the study, the references are well-cited. Nothing from any previously published articles or textbooks has been withdrawn.
Journal Article
Investigating slope stability of multiple stopes prone to instability in the Ziluoyi iron ore mining site
The ore mining sites commonly experience slope instability, which is causing concern for the workers’ safety and the operation’s stability. Considering the Ziluoyi iron ore mining site as a case study, uniaxial compression strength and shear tests are performed on the lower disk peripheral rock, ore body, and upper disk peripheral rock, leading to the extraction of compressive strength and elastic modulus (lower disk: 77.7 MPa–9.093 GPa; ore body: 19.6 MPa–4.619 GPa; upper disk: 55.47 MPa–5.573 GPa). Further, using the Hoek–Brown criterion in conjunction with the Moher–Columb criterion, the cohesion and internal friction angle of various samples are appropriately determined (lower disk: 21.124 MPa–35.614°; ore body: 21.66 MPa–26.5°; upper disk: 42.916 MPa–25.743°). By employing an appropriate rock mass reduction model, its constants (
m
and
s
) and RMR score for the consisting layers (schist layer and ore body) of the three understudy slopes (Slope#1–Slope#3) are evaluated. An effective algorithm based on the Morgenstern–Price method is employed and its effectiveness is also proved by comparing its factor of safety results with those of Geo-Slope for various slope structures subjected to different loads. Subsequently, the stability analyses of various slopes are methodically examined by predicting the factor of safety values under multiple types of loading (i.e., self-weight + groundwater, slope self-weight + groundwater + blasting vibration force, and self-weight + groundwater + seismic force). The factor of safety values of the slopes pertinent to Slope#1/Slope#2/Slope#3 subjected to the above loading conditions are obtained as 1.354/1.273/1.188, 1.326/1.239/1.169, and 1.321/1.232/1.162, respectively. Upon comparing these results with those of a valid homeland specification, it becomes clear that the results are able to meet safety standards and ensure efficient mine operation.
Journal Article