Showing 6 results for bod
P. Intra, P. Wanusbodeepaisarn, T. Siri-Achawawath,
Volume 15, Issue 3 (September 2019)
Abstract
The object of the present work was to design, construct and evaluate a cylindrical tri-axial charger for charging of submicron aerosol particles by unipolar ions. The corona discharge characteristics, the intrinsic and extrinsic particle charging efficiencies, and the losses of aerosol particles were experimentally evaluated for particle diameters in the range between 50 nm and 500 nm under different operating conditions. The conditions included the corona voltages of about 7.0 to 8.0 kV, the mesh screen voltages of about 100 to 300 V and the aerosol flow rate was set at 1.5 L/min. It was found that the ion current increased from 2.90´10-10 to 3.66´10-8 A and 2.40´10-10 to 1.36´10-7 A and the number concentration of ions increased from 7.50´109 to 5.92´1011 ions/m3 and 6.21´109 to 2.19´1012 ions/m3 when the corona voltage increased from 5.5 to 8.0 kV at the mesh screen voltage between 100 and 300 V, respectively. The intrinsic charging efficiency of particles introduced a constant value of about 99% for particle diameter in the range between 50 nm and 200 nm and decreased with particle diameter in the range between about 300 nm and 500 nm at a given corona voltage. The best extrinsic charging efficiency of the studied charger occurred between 1.32% and 38% for particle diameter in the range from 50 nm to 500 nm at corona and ion trap voltages of about 7.0 kV and 300 V respectively. The highest electrostatic loss of particles was observed at 50 nm particles and it was about 89.08, 90.73 and 91.91% at a mesh screen voltage of about 300 V for corona voltages of about 7.0, 7.5 and 8.0 kV, respectively. Finally, the highest diffusion losses were at about 28.88, 23.03 and 11.15% for singly charged, neutralized and non-charged particles of 500, 500 and 50 nm, respectively.
A. O. Amole, O. E. Olabode, D. O. Akinyele, S. G. Akinjobi,
Volume 18, Issue 3 (September 2022)
Abstract
Milk is one of the important dairy foods, which forms an essential building block in the feed formulation for infant and growing children, and adults alike. However, the quality of the final product largely depends on the temperature of the pasteurization process. It is, therefore, a necessity to ensure that optimum temperature is maintained during pasteurization process, as over-temperature kills all the essential nutrients contained in the final product and similarly, low temperature is not desirable as the final product will not yield the desired nutritional value. As a result, the application of optimal temperature control scheme is a critical requirement for milk pasteurization. It is, on this background, that this paper presents the use of a Proportional (P), Integral (I), Derivative (D) abbreviated as PID controller for optimal control of temperature in the milk pasteurization process. The milk pasteurization temperature was modeled based on the first law of thermodynamics, while three different tuning techniques namely; Zigler-Nichols (ZN), Chien-Hrones-Reswick (CHR) and Cohen-Coon (CC) were employed to tune the PID controller for optimal control of the milk pasteurization temperature. The control schemes were simulated in MATLAB/Simulink, and the performance of each tuning technique was evaluated using the rise time, settling time, peak amplitude, and overshoot. Results showed that ZN tuned PID controller gave the lowest rise time, settling time, and peak amplitude of 0.177s, 0.34s, and 0.993, respectively, while the lowest overshoot of 0% was attained by both ZN and CHR. Based on these results, CC tuned PID controller exhibited moderate rise time of 1.02s, settling time of 6.49s, and overshoot of 5.67%, indicating that its performance is comparatively preferred with respect to other tuning techniques investigated. The results of this research find application in diary industries as it provides insight into the appropriate tuning technique for the PID controller to ensure optimum temperature control during milk pasteurization.
I. K. Okakwu, O. E. Olabode, D. O. Akinyele, T. O. Ajewole,
Volume 19, Issue 2 (June 2023)
Abstract
This paper evaluates the wind potential of some specified locations in Nigeria, and then examines the response of wind energy conversion systems (WECSs) to this potential. The study employs eight probability distribution (PD) functions such as Weibull (Wbl), Rayleigh (Ryh), Lognormal (Lgl), Gamma (Gma), Inverse Gaussian (IG), Normal (Nl), Maxwell (Mwl) and Gumbel (Gbl) distributions to fit the wind data for nine locations in Nigeria viz. Kano, Maiduguri, Jos, Abuja, Akure, Abeokuta, Uyo, Warri and Ikeja. The paper then uses the maximum likelihood (ML) method to obtain the parameters of the distributions and then evaluates the goodness of fit for the PD models to characterize the locations’ wind speeds using the minimum Root Mean Square Error (RMSE). The paper analyses the techno-economic aspect of the WECSs based on the daily average wind speed; it evaluates the performance of ten 25 kW pitch-controlled wind turbines (WT1 – WT10) with dissimilar characteristics for each location, including the cost/kWh of energy (COE) and the sensitivity analyses of the WECSs. Results reveal that Ryh distribution shows the best fit for Kano, Jos, Abeokuta, Uyo, Warri and Ikeja, while the Lgl distribution shows the best fit for Maiduguri, Abuja and Akure due to their minimum RMSE. WT7 achieves the least COE ranging from $0.0328 in Jos to $4.4922 in Uyo and WT5 has the highest COE ranging from $0.1380 in Ikeja to $53.371 in Uyo. The paper also details the sensitivity analysis for the technical and economic aspects.
M. Nezhadshahbodaghi, K. Bahmani, M. R. Mosavi, D. MartÃn,
Volume 19, Issue 2 (June 2023)
Abstract
Today, it can be said that in every field in which timely information is needed, we can use the applications of time-series prediction. In this paper, among so many chaotic systems, the Mackey-Glass and Loranz are chosen. To predict them, Multi-Layer Perceptron Neural Network (MLP NN) trained by a variety of heuristic methods are utilized such as genetic, particle swarm, ant colony, evolutionary strategy algorithms, and population-based incremental learning. Also, in addition to expressed methods, we propose two algorithms of Bio-geography-Based Optimization (BBO) and fuzzy system to predict these chaotic systems. Simulation results show that if the MLP NN is trained based on the proposed meta-heuristic algorithm of BBO, training and testing accuracy will be improved by 28.5% and 51%, respectively. Also, if the presented fuzzy system is utilized to predict the chaotic systems, it outperforms approximately by 98.5% and 91.3% in training and testing accuracy, respectively.
Majid Najjarpour, Behrouz Tousi, Shahaboddin Yazdandoust Moghanlou,
Volume 20, Issue 1 (March 2024)
Abstract
In recent decades, because of the rapid population growth of the world, considerable changes in climate, the reduction of fossil fuel sources to consume the traditional power plants and their high depreciation, and the increase in fuel prices. Due to the increased penetration of DG units which have a random nature into the power system, the ordinary equations of power flow must be changed. For the power system to operate in a stable condition estimating future demand and calculating the important and operational indexes such as losses of the power system is an important duty that must be done precisely and rapidly. In this paper, the Improved Taguchi method and phasor measurement unit are used to model the uncertainties of DGs and estimate the error of voltage, respectively. The results show that the magnitude error and the angle error of voltage are decreased using PMU. The applied optimal power flow and state estimations are analyzed and verified using standard IEEE 30-bus and 14-bus test power systems by MATLAB, and MINITAB softwares. The Made Strides Taguchi strategy appears to have modeled the DG units precisely and successfully, and using the PMU, the mistake of the point and greatness estimation is exceptionally moot. The values that were evaluated are very close to the values that were done by the Newton-Raphson stack stream.
Amir M. Zaker, Mohammad Bod, Hamid G. Bafghi,
Volume 22, Issue 4 (December 2026)
Abstract
This paper proposes a novel wideband circularly polarized L/S feed system for portable satellite communications. The feed system integrates a multi-stage septum polarizer, a sloped waveguide transition, and an axial choke conical horn to ensure uniform reflector illumination of a 3-meter reflector antenna. Unlike existing septum-based feed designs, the proposed structure achieves an ultra-wide 47% fractional bandwidth (1.6–2.6 GHz) with an axial ratio below 2 dB. It is explicitly optimized for use as a reflector feed rather than as a standalone antenna. A foldable multi-piece strut mechanism is introduced to enhance portability and facilitate field deployment. In addition, a convex plate at the reflector vertex is employed to reduce feed blockage and improve gain, particularly at higher frequencies. Simulation and measurement results are compared, demonstrating superior performance of the proposed antenna to existing solutions, including high isolation (>15 dB) between ports and sidelobe levels better than 26 dB. The combination of wideband circular polarization, reflector-level optimization, and mechanical portability distinguishes this work from prior septum-horn and portable reflector-antenna solutions.
