Method for Determining the Schottky Diodes Electrical Parameters

When studying the operation of Schottky diodes the most important electrical parameters are the height of the potential barrier, the coefficient of ideality, the saturation current and the series resistance of the material and contacts. These parameters can be determined from the experimental volt-ampere characteristics. The article considers the methods of determining these electrical parameters of Schottky diodes, as well as the factors that affect the accuracy of calculations. The existing methods for calculating the electrical parameters of Schottky diodes are analyzed, namely: the method of Norde, Roderick, Chong, Sato and the method of direct approximation. The Norde method was developed for a coefficient of ideality equal to one for cases where the effect of series resistance on the I–V characteristics makes a significant error in determining the barrier height by simpler methods. A significant disadvantage of this method is that in many cases the coefficient of ideality is not equal to one, even in the case of an ideal diode, which makes an error in the calculation result. The advantage of Roderick's method is the possibility of describing the forward and reverse branches of the I–V characteristics by one dependence, as well as taking into account measurements at voltages less than tripled temperature potential. The disadvantages of this method include the lack of consideration of the effect of series resistance, which may result in additional errors. The main advantage of the Chong method is the determination of the series resistance together with the height of the barrier and the coefficient of ideality, which not only provides additional information about the contact, but also convenient in terms of automation of the calculation process. The disadvantages include the possibility of applying the method only to the voltage range above the tripled temperature potential. The disadvantages of Sato methods and direct approximation include the fact that the calculation is performed at one point of the I–V curve, which can negatively affect the accuracy. It is also shown that these methods have a significant standard deviation of the calculated values from the experimental ones, which is due to the temperature dependence of the height of the potential barrier and the dependence of the coefficient of ideality on the voltage. Also, the reason for the increase in the calculation error of the electrical parameters in all five methods is the decrease in the length of the I–V characteristics in logarithmic coordinates. When using any of the considered methods, the calculation is performed in logarithmic coordinates, which complicates the determination of the boundaries of the I–V section, where the dependence of the parameters of the Schottky diode on the voltage is insignificant. A new algorithm for calculating the electrical parameters of Schottky diodes has been developed. Based on the conjugate gradient method, a method for optimizing the algorithm for calculating the electrical parameters of Schottky diodes was developed, which made it possible to reduce the standard deviation by more than an order of magnitude. The developed algorithm is verified by comparing the calculated volt-ampere characteristics of Schottky diodes with those obtained experimentally. To construct the calculated volt-ampere characteristics, the values of the electrical parameters of Schottky diodes were used, which were determined by the presented algorithm. The results of the calculation are in good agreement with the experimental data. The proposed method can be used both in scientific work to study the properties of semiconductor materials, and in production to control the quality of Schottky diodes.

Internet of Things-based Hydroponic: Literature Review

Hydroponics is a method of growing crops without using soil, with the benefits of controlling the environment and nutrients, conserving water, and reducing labor. The applied technology is used to improve results that have consistency. This research was conducted with the aim of knowing the IoT devices and platforms used in the development of IoT-based hydroponics. Data obtained from the website garuda.ristekbrin.go.id and www.sciencedirect.com from 2016 to 2021. This study is a literature review using the PRISMA method. This method is used for literature review using a systematic and structured basic framework. The results of this study indicate that the variables measured are Temperature, Potential Hydrogen (pH), Total Dissolve Solid, Water Temperature, Humidity, UV, Carbon Dioxide, Soil Moisture and Electrical Conductivity. The device used is the ESP8266, Arduino, and Raspberry PI with the MySQL, Thingspeak, Firebase, Domoticz, and Wyliodrin IoT Platforms.

Machine Learning Applied to the Oxygen-18 Isotopic Composition, Salinity and Temperature/Potential Temperature in the Mediterranean Sea

This study proposed different techniques to estimate the isotope composition (δ18O), salinity and temperature/potential temperature in the Mediterranean Sea using five different variables: (i–ii) geographic coordinates (Longitude, Latitude), (iii) year, (iv) month and (v) depth. Three kinds of models based on artificial neural network (ANN), random forest (RF) and support vector machine (SVM) were developed. According to the results, the random forest models presents the best prediction accuracy for the querying phase and can be used to predict the isotope composition (mean absolute percentage error (MAPE) around 4.98%), salinity (MAPE below 0.20%) and temperature (MAPE around 2.44%). These models could be useful for research works that require the use of past data for these variables.

The Impact of Global Climate Change to Climate Condition of Bengkulu Watershed, Indonesia

Global climate change that occurred in this century can affect the pattern of rain and increase in temperature on earth. This study aims to determine and analyze the increase in rainfall, air temperature, potential evapotranspiration and actual evapotranspiration in the Bengkulu watershed. For this reason, the regional rainfall is calculated using the Thiessen Polygon, the mean air temperature of the watershed based on the median elevation, potential evapotranspiration using the Thornthwaite Method and actual evapotranspiration using the basis of the difference in rainfall to potential evapotranspiration. The results showed that every year there was an increase in rainfall, air temperature, potential evapotranspiration and actual evapotranspiration in the Bengkulu Watershed. In the 2009-2013 period, the average annual rainfall of 3,581 mm increased to 3,641 mm in the 2014-2018 period. For air temperature, the average monthly air temperature in the Bengkulu Watershed for the 2009-2013 period was 25.8°C, while the air temperature in the 2014-2018 period was 26.1°C. This means that in a period of 5 years there is an increase in temperature of 0.3°C. Furthermore, due to the increase in air temperature, there was an increase in the average monthly potential evapotranspiration from the 2009-2013 period to the 2014-2018 period, namely from 1,493 mm to 1,537 mm, while for actual evapotranspiration there was an increase from 1,486 mm to 1,518 mm.

ENERGY EFFICIENT TECHNOLOGY OF DRYING AND STORAGE OF SEEDS OF GRAIN CROPS WITH THE USE OF HEAT PUMPS

Energy efficiency of the drying process today is the main parameter that affects the choice of drying mode. Seed requires more careful selection of technology and equipment, which is associated with quality characteristics. Seed material to maintain high germination is dried at low temperatures, the operation of the grain dryer at high temperatures significantly reduces the quality and requires the development of special technology for the production and storage of seeds of cereals. The article reviews the increase in energy efficiency of equipment for drying grain seeds. Traditional seed drying technologies are too expensive and significantly increase the cost. The developed energy-efficient technologies are more aimed at drying food grain with a process at high temperature, which allows to use the high temperature potential of spent coolant at the outlet of the dryer, which can be recycled and re-directed to heat the drying agent at the dryer. When drying the seeds of cereals, it is necessary to carry out the process at low temperatures, which reduces the efficiency of the temperature potential of the spent coolant. Therefore, to increase the energy efficiency of the drying process and technology, it is proposed to use heat pumps that ensure the quality of seed material. The article also analyzes heat losses and recommends measures to reduce losses during drying, which provide for the use of heat pump units. Energy-efficient technology of drying and storage of seeds of grain crops provides operations of sifting, drying, storage, division into fractions, pickling, packing in bags. A 5-zone grain dryer with step drying modes using a heat pump and a generator motor has been developed for seed grain. Comparison of energy efficiency of different drying units showed that the proposed technical solutions are verified by calculations and heat consumption is much lower and is 3024 kJ / kg vip . moisture.

Experimental Analysis of a Novel Solar Pond Driven Thermoelectric Energy System

This paper describes an experimental study on a combined assembly of a solar pond and two-phase thermosyphon toward thermoelectric power generation under actual weather conditions and proposes its mandatory association with the biomass energy-based system. Experiments under the studied solar radiation intensity ranging between 26 W/m2 and 976 W/m2 reveal that the maximum steady-state temperature potential during the actual operation of a solar pond is not sufficient to generate the minimum threshold thermoelectric voltage for deriving necessary power needed to recharge a 12 V battery. It is also highlighted that solar radiation heats both the upper and the lower layers nearly equally; however, the heat is lost at a faster rate from the upper layer than the lower layer. Consequently, with the passage of time, the temperature of the lower layer rises, and interestingly, the probability of obtaining maximum voltage during a day is maximum during the early morning. Under the present set of conditions, the maximum temperature gain is 26.58 °C, whereas a minimum temperature potential of 45.62 °C is found necessary to produce the required voltage. The economic analysis of the proposed system reveals that the electricity generation obtained from the proposed system is better than diesel power generation. In particular, the system is suitable for locations where access to the conventional grid-based power is difficult. The work opens opportunities and establishes the necessity of developing low-cost thermoelectric materials for further improving the cost of power generation.