Development of a Pseudo-Closed Loop Solar Collector Sun Tracking System with Optimized Set-Point Paths for Flat Plate Payload

This paper provides the theoretical framework for the development of a pseudo-closed loop solar tracking system incorporating a microcontroller for a flat payload, where the outputs of the system (the slope and the azimuth angles of the payload) are observed and the set-points for the system are to be optimally computed by the microcontroller. It also presents, from literature, the equations and models solar angles and incident angles for the development of the optimum set point path for the tracking, and gives the outline of the signal flow plan, as well as the corresponding flowchart, for the tracking system’s components interaction. The concept would provide a cheaper and simpler alternative to dual axis solar tracking incorporating solar sensors. The models presented here are adaptable to any geographical location in Nigeria and globally

Investigative Study on the Use of De-Oiled Palm Kernel Cake for Biogas Production

Availability of Palm Kernel Cake (PKC) has increased due to the increase in the number of cottage oil palm processing industries in developing countries. A quest for clean energy from bio-waste is also on the increase. This study aims at investigating the biogas generating capacity of de-oiled PKC and its corresponding methane content. De-oiled PKC and a mixture of de-oiled PKC and fresh sugar cane chips were used as the two bio-feed samples in a laboratory anaerobic digestion set up. A theoretical approach was also used to determine the expected methane content in the biogas. Laboratory results for de-oiled PKC gave the volume by weight of bio-feed for biogas and methane to be 12.7 ml/g and 4.2 ml/g respectively and that of the combination of de-oiled PKC and fresh sugar cane chips to be 3.15 ml/g and 1.25 ml/g respectively. The measured methane composition for de-oiled PKC and that of the combination of de-oiled PKC and fresh sugar cane chips to be 33% and 40% respectively while the theoretical estimates were 33.5% and 41.1% respectively. The study shows that de-oiled palm kernel cake has biogas/methane generation potential whose quality can be improved by the addition of other biogas producing wastes.KEYWORDS: Biogas, Agro-Industrial Waste, Palm Kernel Cake, Anaerobic Digestion, Wastewater

Thermodynamics and adsorption isotherms for the biosorption of Cr(VI), Ni(II) and Cd(II) onto maize cob

The use of maize (Zea mays) cob for the biosorption of Cr(VI), Ni(II) and Cd(II) is reported. Biosorption experiments were carried out using batch process with 8g weight of adsorbent and variable adsorbate concentrations. Variations in the concentration of the different adsorbates during the adsorption process were monitored by the use of Shimadzu AA650 Double Beam Atomic Absorption/Flame spectrophotometer. Thermodynamic quantities such as ΔH and ΔS were determined in which ΔH varied from 1,271.21Jmol-1 to 1,466.59Jmol-1 at 20mg/L adsorbate concentration and 1,276.20 to 1,872.42Jmol-1 at 60mg/L suggesting increasing endothermicity of the adsorption process. The adsorption process was found to be spontaneous, with spontaneity increasing with increase in adsorbate concentration and temperature. Also, the ΔG values suggested high affinity of Cr over the other adsorbates. Equilibrium data were tested using Freundlich and Langmuir adsorption isotherms. The values of the numeric constants n and KF from Freundlich plots and the linearity of their plots suggested a chemisorption process closely defined by Freundlich isotherm.Keywords: Adsorbate, Adsorbent, Adsorption isotherms, Maize cob, Thermodynamic

Modification of Thermal Hydraulic Transient Models for the Miniature Neutron Source Reactor

A modified Miniature Neutron Source Reactor (MNSR) model dealing with transient thermal hydraulic problem is presented. The model based on lumped parameter method is adopted in this work to numerically solve a system of coupled algebraic and differential equations governing heat transfer in MNSR, using MATLAB solver for variable order method in stiff differential equations and Differential-Algebraic equations, coupled with Maple soft. The simulated results obtained from the model were generally in agreement when compared with reactor operation data recorded from 0 to 270 minutes during experiments. Radiating energy of Fuel and clad and heat transferred at the gap or clearance were taken in to account. Fuel and clad temperatures as well as various temperatures at different sections of the reactor were predicted with the model, in addition to the effect of the installed chiller on the reactor coolant

Fuzzy antiwindup schemes for NCTF control of Point-Topoint (PTP) positioning systems

The positioning systems generally need a controller to achieve high accuracy, fast response and robustness. In addition, ease of controller design and simplicity of controller structure are very important for practical application. For satisfying these requirements, NCTF (nominal characteristic trajectory following) controller has been proposed as a practical PTP positioning control. However, the effect of actuator saturation can not be completely compensated due to integrator windup because of plant parameter variations. This study presents a method to improve the NCTF controller for overcoming the problem of integrator windup by adopting fuzzy anti-windup schemes. Two fuzzy antiwindup schemes based on Mamdani and Takagi-Sugeno fuzzy system are developed and evaluated their effectiveness. The improved NCTF controller with the proposed fuzzy anti-windup schemes is evaluated through simulation using dynamic model of a rotary positioning system. The results show that the improved NCTF controller with Takagi-Sugeno-based fuzzy windup is the best scheme to compensate for the effect of integrator windup

Application of intelligent technique for development of Colpitts oscillator

In this paper, new method of Colpitts oscillator designing through combination of Genetic Algorithm and Artificial Neural Network (ANN) has been suggested. The Thevenin's resistors for the common base Colpitts oscillator are optimized through application of GA and ANN. The developed common base Colpitts oscillator has shortest transient time response and stable Direct Current (DC) stability in the long term operation. Involvement of GA and ANN successfully optimize between transient time response and steady state response of common base oscillator. Application of these two artificial intelligent techniques assist faster selection of optimizes components values such as resistance values during circuit development rather than conventional method which used intuition techniques to develop the circuit

Biosorption of Cr(VI), Ni(II) and Fe(II) by maize (zea mays) cob

The experimental results for the biosorption of Cr(VI), Ni(II) and Fe(II) onto maize cob were reported. The adsorbents efficiency on the bioremediation of these metals was estimated from the change in the percent adsorbate removal with (i) adsorbent dosage (ii) adsorbate initial concentration, (iii) variation in pH of the adsorbate solution and (vi) increase in surface area of the adsorbate. Untreated Maize Cob (MC) was found to demonstrate high affinity for Fe(II) in both granular and powdered form in such a way that 2g Powdered Maize Cob (PMC) was able to remove about 89% whereas a 100% removal was observed with 8g adsorbent. On the other hand MC showed low affinity for Ni(II) in the sense that even with the powdered form, % removal does not vary significantly between 2 and 8g.Keywords: Zea mays, adsorption, adsorbent, metal ion, % remova

Evaluating the effectiveness of time-domain features for motor imagery movements using SVM

Motor imagery electroencephalogram signals are the only bio-signals that enable locked-in patients, who have lost control over every motor output, to communicate with and control their surroundings. Brain Machine Interface is collaboration between a human and machines, which translates brain waves to desired, understandable commands for a machine. Classification of motor imagery tasks for BMIs is the crucial part. Classification accuracy not only depends on how accurate and robust the classifier is; it is also about data. For well separated data, classifiers such as kernel SVM can handle classification and deliver acceptable results. If a feature provides large interclass difference for different classes, immunity to random noise and chaotic behavior of EEG signal is rationally conformed, which means the applied feature is suitable for classifying EEG signals. In this work, in order to have less computational complexity, time-domain algorithms are employed to motor imagery signals. Extracted features are: Mean Absolute Value, Maximum peak value, Simple Square Integral, Willison Amplitude, and Waveform Length. Support Vector Machine with polynomial kernel is applied for classification of four different classes of data. The obtained results show that these features have acceptable, distinct values for different these four motor imagery tasks. Maximum classification accuracy belongs to contribution of Willison amplitude as feature and SVM as classifier, with 95.1 percentages accuracy. Where, the lowest is the contribution of Waveform Length and SVM with 31.67 percentages classification accuracy

Semi-analytical study of a one-dimensional contaminant flow in a finite medium

The Bubnov-Galerkin weighted residual method was used to solve a one-dimensional contaminant flow problem in this paper. The governing equation of the contaminant flow, which is characterized by advection, dispersion and adsorption was discretized and solved to obtain the semi-analytical solution. The adsorption isotherm was assumed to be of Freudlich type. The results obtained were expressed in graphical form to show the effect of change in the parameters on the concentration of the contaminants. From the analysis of the results, it was discovered that the contaminant concentration decreases with increase in the distance from the origin as the dispersion and velocity coefficient decrease.Keywords: Adsorption, advection, Bubnov-Galerkin weighted residuals, contaminant, dispersio

SOLVABILITY OF A NORMAL SUBGROUP IN RELATION TO ITS CHARACTER DEGREES

In this work, how the structure of a normal subgroup of a group G is influenced by the degrees of an appropriate subset of irreducible character of a group G was verified. The characters that were used in controlling the structure of N Δ G are exactly those whose kernels do not contain N.Given that N Δ G,Irr (G/N) =  {Є Irr (G)/N  ker }andcd (G/N) = { (1) /   Irr (G/N)}Â