Roba Tarek AbdelFatah^*, Irene S. Fahim, Mohamed Mahran Kasem

Frontiers in Heat and Mass Transfer, Vol.22, No.1, pp. 317-339, 2024, DOI:10.32604/fhmt.2023.044706

Abstract Parabolic trough solar collectors (PTCs) are among the most cost-efficient solar thermal technologies. They have several applications, such as feed heaters, boilers, steam generators, and electricity generators. A PTC is a concentrated solar power system that uses parabolic reflectors to focus sunlight onto a tube filled with heat-transfer fluid. PTCs performance can be investigated using optical and thermal mathematical models. These models calculate the amount of energy entering the receiver, the amount of usable collected energy, and the amount of heat loss due to convection and radiation. There are several methods and configurations that have been developed so far; however,… More > Graphic Abstract

S. Dickson¹, S. Padmasekaran¹, Pushpendra Kumar^2,*, Kottakkaran Sooppy Nisar³, Hamidreza Marasi⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.3, pp. 2265-2287, 2024, DOI:10.32604/cmes.2023.030286

Abstract This research examines the transmission dynamics of the Omicron variant of COVID-19 using SEIQI_cRVW and SQIRV models, considering the delay in converting susceptible individuals into infected ones. The significant delays eventually resulted in the pandemic’s containment. To ensure the safety of the host population, this concept integrates quarantine and the COVID-19 vaccine. We investigate the stability of the proposed models. The fundamental reproduction number influences stability conditions. According to our findings, asymptomatic cases considerably impact the prevalence of Omicron infection in the community. The real data of the Omicron variant from Chennai, Tamil Nadu, India, is used to validate the… More >

Muhammad Farman^1,2,4, Ali Akgül^3,9,*, Mir Sajjad Hashemi⁵, Liliana Guran^6,7, Amelia Bucur^8,*

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.2, pp. 1385-1403, 2024, DOI:10.32604/cmes.2023.028803

Abstract New fractional operators, the COVID-19 model has been studied in this paper. By using different numerical techniques and the time fractional parameters, the mechanical characteristics of the fractional order model are identified. The uniqueness and existence have been established. The model’s Ulam-Hyers stability analysis has been found. In order to justify the theoretical results, numerical simulations are carried out for the presented method in the range of fractional order to show the implications of fractional and fractal orders. We applied very effective numerical techniques to obtain the solutions of the model and simulations. Also, we present conditions of existence for… More >

Tariq T. Alshammari¹, Mohd Tahir Ismail¹, Nawaf N. Hamadneh^3,*, S. Al Wadi², Jamil J. Jaber², Nawa Alshammari³, Mohammad H. Saleh²

Intelligent Automation & Soft Computing, Vol.35, No.3, pp. 2589-2601, 2023, DOI:10.32604/iasc.2023.024001

Abstract In this study, we proposed a new model to improve the accuracy of forecasting the stock market volatility pattern. The hypothesized model was validated empirically using a data set collected from the Saudi Arabia stock Exchange (Tadawul). The data is the daily closed price index data from August 2011 to December 2019 with 2027 observations. The proposed forecasting model combines the best maximum overlapping discrete wavelet transform (MODWT) function (Bl14) and exponential generalized autoregressive conditional heteroscedasticity (EGARCH) model. The results show the model's ability to analyze stock market data, highlight important events that contain the most volatile data, and improve… More >

Nawaf N. Hamadneh¹, Waqar A. Khan², Ilyas Khan^{3, *}

CMC-Computers, Materials & Continua, Vol.65, No.2, pp. 1015-1032, 2020, DOI:10.32604/cmc.2020.011476

Abstract One of the most significant considerations in the design of a heat sink is thermal management due to increasing thermal flux and miniature in size. These heat sinks utilize plate or pin fins depending upon the required heat dissipation rate. They are designed to optimize overall performance. Elliptical pin fin heat sinks enhance heat transfer rates and reduce the pumping power. In this study, the Firefly Algorithm is implemented to optimize heat sinks with elliptical pin-fins. The pin-fins are arranged in an inline fashion. The natureinspired metaheuristic algorithm performs powerfully and efficiently in solving numerical global optimization problems. Based on… More >

Lanting Zhang, Laifu Guo, Qiang Rong^*

Energy Engineering, Vol.117, No.4, pp. 195-207, 2020, DOI:10.32604/EE.2020.010617

Abstract The various ply parameters of composite wind turbine blade have crucial influence, of respectively varying degree, on the static strength and stiffness of the blade, elements closely related to its performance. In this article, the method of the single-parameter sensitivity analysis is presented. A 1.5 MW wind turbine blade is considered as the study object, where the load of the blade is calculated and the respective finite element model is established. According to engineering practice, the investigation range of ply parameters is determined, and the test design scheme of ply parameter for the blade is constructed. The Tsai-Wu failure factor… More >

Amado Alvarez^1,2, Enrique Rubiños Panta¹, Francisco Gavi Reyes¹, Juan José Alarcón Cabañero², Elizabeth Hernández Acosta³, Carlos Ramírez Ayala¹, Enrique Mejía Saenz¹, Francisco Pedrero Salcedo², Emilio Nicolas Nicolas², Enrique Salazar Sosa⁴

Phyton-International Journal of Experimental Botany, Vol.75, pp. 71-83, 2006, DOI:10.32604/phyton.2006.75.071

Abstract A water quality index as a standardized method to compare the category in an integral way, between locations and through time, of the different water, river and stream storages of the Amajac river basin was developed. In addition, it is possible to predict the degree of contamination and establish planning strategies in the management of the water resources for the river basin in issue. The used methodology was based in the quantitative expression of water quality. Three samplings were made (2005-2006) and Dissolved Oxygen, Coliform in feaces, pH, Oxygen Biochemical Demand, Nitrates, Total Phosphorus, Turbidity and Dissolved Total Solids were… More >

I. Kvasnica¹, P. Kvasnica²

CMES-Computer Modeling in Engineering & Sciences, Vol.107, No.6, pp. 447-462, 2015, DOI:10.3970/cmes.2015.107.447

Abstract The issue of simulation of decentralized mathematical models is discussed in the paper. The authors’ knowledge is based on a theory of design of decentralized computer control systems. Their knowledge is gained in the process of designing mathematical models that are simulated. A decomposed control system is required to meet the conditions of observation and control. The methodology of a multi-model design is based on main principles of object orientation such as abstraction, hierarchy, and modularity. Modelling on a parallel architecture has an impact on a simulator system. The system is defined by the equations shown below. An important part… More >