Average Current Through a Single-electron Transistor Under Fluctuations of an Observer’s Frame of Reference
Issue:
Volume 7, Issue 5, September 2019
Pages:
118-124
Received:
13 August 2019
Accepted:
28 August 2019
Published:
16 September 2019
Abstract: The average current through a single-electron transistor (SET) under fluctuations of an observer’s frame of reference (OFR) is reported. To date, the average current through a SET has been studied under the assumption that an OFR remains constant throughout the performance of measurements of the current; thus, it remains an unsolved problem as to what is measured of the current when the OFR is assumed to fluctuate. In this paper, a SET comprising a source, drain, and single channel is considered, where an OFR is assumed to be matched to the electrochemical potential energy of the drain of the SET. The average current through the SET for two types of OFR fluctuation is formulated: periodic-square-wave fluctuation and periodic-sawtooth-wave fluctuation, in time representations. Under these types of fluctuation, the average current exhibits a zero-bias Coulomb peak—the amplitude of which gradually increases with the amplitude of the fluctuation type divided by temperature. The amplitude of the zero-bias Coulomb peak is greater in the case of periodic-square-wave fluctuations. Therefore, the amplitude of the zero-bias Coulomb peak together with a varying of both the energy of the channel and the temperature has the potential to reveal the distribution of fluctuations of an OFR.
Abstract: The average current through a single-electron transistor (SET) under fluctuations of an observer’s frame of reference (OFR) is reported. To date, the average current through a SET has been studied under the assumption that an OFR remains constant throughout the performance of measurements of the current; thus, it remains an unsolved problem as to w...
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Sunshine and Temperature Dependent Models for Estimating Global Solar Radiation Across the Guinea Savannah Climatic Zone of Nigeria
Davidson Odafe Akpootu,
Bello Idrith Tijjani,
Usman Mohammed Gana
Issue:
Volume 7, Issue 5, September 2019
Pages:
125-135
Received:
26 August 2019
Accepted:
24 September 2019
Published:
30 October 2019
Abstract: This study investigates the most accurate sunshine and temperature dependent models for estimating global solar radiation over Makurdi and Ibadan situated in the Guinea savannah of Nigeria by comparing nine (9) different existing sunshine dependent models. The study also proposed two temperature dependent models that took the form of quadratic logarithmic and quadratic exponential and were compared to three existing temperature dependent models (Chen, Hargreaves and Samani (HS) and Garcia). The measured monthly average daily global solar radiation, sunshine hours, maximum and minimum temperature meteorological parameters during the period of thirty one (1980-2010) years was utilized and the accuracy of the sunshine and temperature dependent models to ascertain the most suitable models in each location were tested using seven various statistical validation indicators of coefficient of determination (R2), Mean Bias Error (MBE), Root Mean Square Error (RMSE), Mean Percentage Error (MPE), t-test, Nash-Sutcliffe Equation (NSE) and Index of Agreement (IA). The results revealed that the exponent sunshine dependent model proposed by Bakirci and the linear exponential sunshine dependent model proposed by Bakirci were found more accurate for estimating global solar radiation in Makurdi and Ibadan respectively. The proposed quadratic logarithmic and quadratic exponential temperature dependent models were found more suitable for estimating global solar radiation in Makurdi and Ibadan respectively. These recommended models can be found appropriate, if properly calibrated in regions with similar climatic information. The HS temperature dependent model evaluated in this study for Ibadan was compared with those available in literatures and was found more suitable. Furthermore, the most suitable sunshine dependent model was found more suitable for global solar radiation estimation when compared to the most suitable temperature dependent model in each of the studied locations and this was testified from the figures of the comparison between the measured and estimated sunshine and temperature dependent models as the sunshine dependent models depicts the best fitting with the measured global solar radiation data.
Abstract: This study investigates the most accurate sunshine and temperature dependent models for estimating global solar radiation over Makurdi and Ibadan situated in the Guinea savannah of Nigeria by comparing nine (9) different existing sunshine dependent models. The study also proposed two temperature dependent models that took the form of quadratic loga...
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