Current Issue : October - December Volume : 2020 Issue Number : 4 Articles : 5 Articles
The electricity needs of populations in Cameroon are increasing and are still\nvery inadequate. Companies, public buildings and households are facing frequent\nblackout which constrain development and social well-being. Therefore,\nthe present work tried to forecast the electricity demand in the residential\nsector in Cameroon, in order to contribute significantly to the mastery of\nelectricity consumption and highlight decision-makers in this sector. Six macroeconomics\nparameters covering the period 1994-2014 are used for these\nissues. Stationarity tests within gross domestic product, gross domestic product\nper capita, electricity consumption, population and numbers of subscribers\nand households respectively; reveal that all the series are I (1). Thus, the\nVAR (Vector Autoregressive) model has been retained to forecast the electricity\ndemand until 2020. The cusum test and the cusum of squared test attest\nthe stability of that model with a margin of error of 0.02%. Previsions are\nthen more reliable and show that the electric request will skip from 1721\nGWh in 2014 to more than 2481 GWh in 2020 approximatively, following a\ngrowing yearly rate of 5.36%. In order to reach its emergence, Cameroon ought\nto speed up its production in the domain of hydroelectric and thermal grid in\norder to meet the requirements in electric power in short and long term....
In this article, the adaptive neuro-fuzzy inference system (ANFIS) and multiconfiguration gas-turbines are used to predict the\noptimal gas-turbine operating parameters. The principle formulations of gas-turbine configurations with various operating\nconditions are introduced in detail. The effects of different parameters have been analyzed to select the optimum gas-turbine\nconfiguration. The adopted ANFIS model has five inputs, namely, isentropic turbine efficiency (Teff ), isentropic compressor\nefficiency (Ceff ), ambient temperature (T1), pressure ratio (rp), and turbine inlet temperature (TIT), as well as three outputs, fuel\nconsumption, power output, and thermal efficiency. Both actual reported information, from Baiji Gas-Turbines of Iraq, and\nsimulated data were utilized with the ANFIS model. The results show that, at an isentropic compressor efficiency of 100% and\nturbine inlet temperature of 1900 K, the peak thermal efficiency amounts to 63% and 375MW of power resulted, which was the\npeak value of the power output. Furthermore, at an isentropic compressor efficiency of 100% and a pressure ratio of 30, a peak\nspecific fuel consumption amount of 0.033 kg/kWh was obtained. The predicted results reveal that the proposed model\ndetermines the operating conditions that strongly influence the performance of the gas-turbine. In addition, the predicted\nresults of the simulated regenerative gas-turbine (RGT) and ANFIS model were satisfactory compared to that of the foregoing\nBaiji Gas-Turbines....
Leakage coaxial cable is a kind of coaxial cable with various slot structures on the outer conductor of the cable. It can transmit\nsignal and transmit or receive signal and has dual functions of signal transmission line and antenna. Leakage cable has the\nadvantages of strong environmental adaptability, uniform signal coverage, and less attenuation. It is not only widely used in closed\nor semiclosed space with high signal reception quality, such as tunnels, subway, underground parking lot, and elevators but also\ncan realize security and theft-proof monitoring and protection in some areas, such as oil wells, mining fields and natural resource\nprotection areas, military fortresses, museums, airports, banks, and schools. This paper introduces the classification and electrical\nparameters of leaky coaxial cables. On the basis of U-groove leaky coaxial cables, the relationship between the parameters of\ngroove holes in U-groove and the loss of leaky coaxial cables is simulated and analyzed by HFSS software.Theimproved method of\nU-groove structure is obtained, and the curved hook-groove leaky coaxial cables are designed according to this method. The\nsimulation results show that the coupling loss of the cable is lower than that of the U-groove leakage cable, and the transmission\nloss is still within the national standard. It lays a theoretical foundation for the design and development of leaky coaxial cable with\nlow coupling loss....
Abstract: In this work, a semi-empirical relationship of carbon dioxide emissions with atmospheric\nCO2 concentrations has been developed that is capable of closely replicating observations from 1751\nto 2018. The analysis was completed using data from fossil-fuel-based and land-use change based\nCO2 emissions, both singly and together. Evaluation of emissions data from 1750 to 1890 yields a\nlinear CO2 concentration component that may be attributed to the net flux from land-use changes\ncombined with a rapidly varying component of the terrestrial sink. This linear component is then\ncoupled across the full-time period with a CO2 concentration calculation using fossil-fuel\ncombustion/cement production emissions with a single, fixed fossil-fuel combustion airborne\nfraction [AFFF] value that is determined by the ocean sink coupled with the remaining slowly\nvarying component of the land sink. The analysis of the data shows that AFFF has remained constant\nat 51.3% over the past 268 years. However, considering the broad range of variables including\nemission and sink processes influencing the climate, it may not be expected that a single value for\nAFFF would accurately reproduce the measured changes in CO2 concentrations during the industrial\nera....
Experimental and computational fluid dynamics (CFD) are investigated\nthrough the vortex tube system. The benefit of vortex tube is a counter flow\ntype tube, which has further designed and fabricated for investigation. The\nwhole set up is consisting of a simple device that can separate a single stream\nof compressed air into two streams; one is at high temperature and the other\nis lower temperature following an inlet gas stream. The advantages of this\ntube are their compactness, safety, and low equipment cost mainly used in\ncooling and heating applications. This study addressed three-dimensional\nflows; the domain is using computational fluid dynamics (CFD) method and\nexperimental approach to optimize the direction of RHVT. Through the CFD\nanalysis, the best cold end diameter (dc), number of nozzles, and the best parameters\nfor obtaining the highest hot gas temperature and lowest cold gas\ntemperature were obtained and verified by experimental procedures....
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