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Measurements on Solar Energy Resources in the Mt. Everest Region
Norsang Gelsor,
Liu Juan,
Tsoja Wangmo,
Lagba Tunzhup,
Nuozhen Gelsor
Issue:
Volume 9, Issue 1, January 2021
Pages:
1-9
Received:
17 December 2020
Accepted:
5 January 2021
Published:
15 January 2021
Abstract: Research on solar radiation in the Mt. Everest region provides great interests for the strategies of solar energy utilization, climate change and environmental sustainability etc. We present measurement results of global horizontal irradiance, solar spectral irradiance and solar UV irradiance performed with the Dutch CMP11 Pyranometers, the German RAMSES Hyperspectral Irradiance Sensors and the Norwegian NILU-UV Irradiance Meters respectively in the Mt. Everest region during 2008 to 2017. The results show that the solar energy resources are extremely rich in that area, the daily maximum of global horizontal irradiance levels are even frequently exceed the solar constant value of 1368W/m2 during monsoon season, from May to August in that region. The highest daily maximum value reached 1500 W/m2 occurred on July 13, 2017. The annual average of the daily global horizontal irradiance is about 18.4 MJ/m2/d, the daily global horizontal irradiance varies from 13.8 to 23.9 MJ/m2/d, indicates that there are abundant solar energy in that alpine zone. The instruments record that even during the winter time (October to January) more than 15 days of each month are absolute clear days, it shows 28 clear days in November of 2016. It points out that more solar energy can be existed during the winter time due to dry season. The solar spectral irradiance was performed for the first time in this special environment presenting the characteristics of solar spectrum over the region. It reveals not only how abundant the spectral irradiance is, but also rich information about the atmospheric composition over the sky. It is well known that the solar UV radiation strongly impacts on the ecological environment and human health. The measurement results of solar UV dose rates as well as their impact factors (ozone and cloud) during the period of 2008 to 2017 are also presented. Satellite data are also used to see how the solar irradiance is distributed over the Himalayan region in summer, including Mt. Everest.
Abstract: Research on solar radiation in the Mt. Everest region provides great interests for the strategies of solar energy utilization, climate change and environmental sustainability etc. We present measurement results of global horizontal irradiance, solar spectral irradiance and solar UV irradiance performed with the Dutch CMP11 Pyranometers, the German ...
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Some Notes on the Proof of Entropy Increase in the Thermalization of Two Blocks
Issue:
Volume 9, Issue 1, January 2021
Pages:
10-14
Received:
14 October 2020
Accepted:
5 November 2020
Published:
22 January 2021
Abstract: The thermalization of two blocks with different initial temperatures in an insulated recipient is an irreversible process, so the entropy of the system will increase during this process. Lima (Eur. J. Phys. 36 (2015) 068001) has given an elegant and concise proof for that which had been proved by Mungan (Eur. J. Phys. 36 (2015) 048004) with a complex method. However, there are still two problems in Lima’s proof: 1. It is assumed that the heat capacities of two blocks are constants, which is not true in most practical cases. 2. An inequality that describes the concavity of the logarithm function was used but it is still relatively uncommon for beginners. In this article, two stricter and simpler proof were given for the problem 1 by making use of 1/T–Q diagram and T-S diagram, respectively. In the Proof by 1/T–Q diagram, the area under the curve of 1/T over the domain [0, Q0] is the value of the entropy change of the cooler block, which is positive; while the area under the curve of 1/T’ over the domain [Q0, 0] is the value of the entropy change of the hotter block, which is negative. It is rather intuitive to compare these two values by using the monotonicity and domains of T and Т’. A similar method is adopted in the proof by T-S diagram. For the problem 2, another proof for the key inequality in Mungan’s paper was given by using elementary geometric method which is really more suitable for physics beginners.
Abstract: The thermalization of two blocks with different initial temperatures in an insulated recipient is an irreversible process, so the entropy of the system will increase during this process. Lima (Eur. J. Phys. 36 (2015) 068001) has given an elegant and concise proof for that which had been proved by Mungan (Eur. J. Phys. 36 (2015) 048004) with a compl...
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A Scaled Effective Medium Theory for Calculation of Resonant and Relaxation Frequency in Magnetic Composites
Issue:
Volume 9, Issue 1, January 2021
Pages:
15-24
Received:
6 December 2020
Accepted:
14 December 2020
Published:
22 January 2021
Abstract: Scaled Effective Medium Theory (ScEMT) is applied to predict magnetic resonant and relaxation frequency in polymer-magnetic particle composites with favorable comparison to measured data. A single scaling function is identified that uses magnetic particulate resonant and relaxation frequencies, or magnetization and anisotropy field, volume fraction and DC susceptibility as predicted by ScEMT. Previous publications demonstrated that ScEMT improved the prediction of DC susceptibility as compared to classical models. Maxwell-Garnett (MGT) and Coherent Model Approximation (CMA) serve as theoretical baselines for comparison. However, both require separate scaling functions in their prediction of resonant and relaxation. Measured data are presented that suggest a single scaling function of ScEMT is sufficient to calculate both parameters. The paper emphasizes the application of the models and shows a wide range of particulate chemistries. ScEMT calculates susceptibility, resonant and relaxation frequency that agree with measurement. The paper concludes by predicting dispersive permeability that represents improvement over both CMA and MGT models. Future studies will address formulation of an EMT model (s) that describe mixtures of hard and soft magnetic materials mixed in a polymer composite. EMT for composite dielectric properties will be expanded to address the chaining. Early results of that effort will be reported in a separate paper.
Abstract: Scaled Effective Medium Theory (ScEMT) is applied to predict magnetic resonant and relaxation frequency in polymer-magnetic particle composites with favorable comparison to measured data. A single scaling function is identified that uses magnetic particulate resonant and relaxation frequencies, or magnetization and anisotropy field, volume fraction...
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A GSM Based Intelligent Solar Energy Measuring System
Salami Olugbenga,
Green Oluwole
Issue:
Volume 9, Issue 1, January 2021
Pages:
25-28
Received:
6 January 2021
Accepted:
14 February 2021
Published:
17 March 2021
Abstract: A Photovoltaic (PV) power monitoring is important in PV systems for proper generation and transmission. With the need to monitor certain parameters like voltage, current and power in order to ascertain the power output of a solar system. In this project design, a GSM solar power monitoring system is designed in order to monitor the voltage, current and output power of a solar system and also transmit the monitored parameters in real time to a remote location via the SMS feature of the GSM technology. An 8 bit 18F452 PIC microcontroller is used as the control unit which controls the Pulse width Modulation (PWM) solar charge controller, IRF3205 MOSFETs as the switching transistors in the charge controller charging a 30AH 12v battery via a 30watts polycrystalline solar panel. Universal asynchronous synchronous receiver and transmitter (USART) is used as protocol for transmission between a Sim 900 GSM module and the microcontroller while the attention (AT) command is used as the communication protocol in sending measured power parameters from the microcontroller to the GSM module which in turn sends the measured parameters as SMS message to a remote location. ACS 712 hall effect current sensor for measuring current and a voltage divider network for measuring the PV cell voltage. The circuit board is printed on a Printed circuit board (PCB) using the traditional transfer method. C programming language is used in writing program codes embedded on the controller. This project design have been able to show that by employing the use of a wireless real time data monitoring (GSM technology), PV systems can be properly monitored remotely for consumption, operation, analysis and isolation in cases of fault detection.
Abstract: A Photovoltaic (PV) power monitoring is important in PV systems for proper generation and transmission. With the need to monitor certain parameters like voltage, current and power in order to ascertain the power output of a solar system. In this project design, a GSM solar power monitoring system is designed in order to monitor the voltage, current...
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