Authors:Taofeek Otunla, Abasikeme Kenneth Umoren Pages: 40 - 51 Abstract: Thorough knowledge of the wind characteristics and variations are of great importance in the development of wind energy resource in any location. This study examines the wind characteristics and assess the potential of two distribution functions in a low wind equatorial region of West Africa. High resolution wind speed and direction data were obtained from a site in Nsukka, a location chosen in the region of study. Diurnal, seasonal and annual variations of both the wind speed and directions were examined. The potentials of two-parameter Weibull distribution and another distribution function based on Maximum Entropy principle (MEP) were assessed using R2 and root mean squared error (RMSE). The results indicated that day-time is windier than night-time. The transitions months of February, March and April have the highest wind speed. The dry season has greater energy potential than rainy season. The predominant wind direction lay within the sectors: South-South-West and East. The predominant wind sector for February, March and April is South-East. The R2 for daily, sub-seasonal day-time and night-time, monthly, and annual ranged between 0.90 and 0.99 for both MEP-based and Weibull distributions. The daily, sub-seasonal day-time and night-time, monthly, and annual RMSE also ranged between 0.011 to 0.075 for MEP-based and Weibull distribution respectively. Thus, both MEP-based and Weibull two-parameter distribution functions can be used to model wind data at the location of study. PubDate: 2023-01-01 Issue No:Vol. 14, No. 2 (2023)
Authors:Khadeejah James Audu , Jamiu Garba, Abdgafar Tunde Tiamiyu, Blessing Ashiodime Thomas Pages: 52 - 65 Abstract: Higher order ordinary differential equations are typically encountered in engineering, physical science, biological sciences, and numerous other fields. The analytical solution of the majority of engineering problems involving higher-order ordinary differential equations is not a simple task. Various numerical techniques have been proposed for higher-order initial value problems (IVP), but a higher degree of precision is still required. In this paper, we propose a novel two-step backward differentiation formula in the class of linear multistep schemes with a higher order of accuracy for solving ordinary differential equations of the fourth order. The proposed method was created by combining interpolation and collocation techniques with the use of power series as the basis function at some grid and off-grid locations to generate a hybrid continuous two-step technique. The method's fundamental properties, such as order, zero stability, error constant, consistency, and convergence, were explored, and the analysis showed that it is zero stable, consistent and convergent. The developed method is suitable for numerically integrating linear and nonlinear differential equations of the fourth order. Four Numerical tests are presented to demonstrate the efficiency and accuracy of the proposed scheme in comparison to some existing block methods. Based on what has been observed, the numerical results indicate that the proposed scheme is a superior method for estimating fourth-order problems than the method previously employed, confirming its convergence. PubDate: 2023-01-01 Issue No:Vol. 14, No. 2 (2023)
Authors:Nur ‘Izqa Ashiqin Mohd Najib, Siti Amira Othman Pages: 1 - 7 Abstract: Conducting polymers have previously been employed in biosensors because they may be used as immobilisation matrices as well as redox systems. Also have numerous uses in medical, pharmacy, environmental monitoring, food and process control. The conductivity of polyaniline-based compositions may be precisely regulated over a broad range. Polyaniline is ease to synthesis, has high conductivity and good performance in biosensor applications. However, polyaniline is not entirely perfect because of its poor solubility in many solvents and low adhesion to different substrate. In this study, hydrochloric acid (HCl) and sulphuric acid (H2SO4) were prepared with different concentration (0.2M, 0.4M, 0.6M, 0.8, 1.0M) for doping process of polyaniline. Fourier-transform Spectroscopy (FTIR), Ultraviolet Spectroscopy (UV-Vis) and Scanning Electron Microscopy (SEM) were used to characterize the properties and morphology of the polyaniline. Four point probe was used to identify the conductivity of the polyaniline sample. FTIR shows a shift peak at benzenoid rings and quioniod rings. Both acids represent that 1.0 M have high absorbance properties. While SEM shows significant different of agglomeration rate for HCl compared to H2SO4. Lastly, the results showed that the conductivity increasing when the concentration of acids increasing. Doping process helps in enhancing the conductivity properties of polyaniline for biosensor application. PubDate: 2022-11-10 Issue No:Vol. 14, No. 2 (2022)
Authors:K. C. Igwe Pages: 8 - 19 Abstract: This paper investigates the degree of influence of weather and the environment on radio signal propagation between a Very High Frequency (VHF) band transmitter and a receiver in the North Central region of Nigeria. Signal strength measurements were made from a Frequency Modulation (FM) station broadcasting at 100.5 MHz using a digital signal level meter. The results obtained showed that received signal strength (RSS) values were higher during the wet season with average values ranging between 41 dBµV and 50 dBµV as compared to lower values of between 36 dBµV and 48 dBµV recorded during the dry season. The computed radio refractivity revealed similar trend of low dry season values in the range of 291 N-units to 345 N-units and high wet season values ranging between 350 N-units and 363 N-units. Also, the cumulative frequency distribution of the signal level computed showed that 50 dBµV had the highest number of samples, while 60 dBµV and 70 dBµV recorded the lowest number of samples. In addition, dry season values of attenuation deduced ranged between 1.6 dB and 2.8 dB, while average wet season attenuation values vary from 1.4 dB to 2.3 dB. Finally, the RSS was modeled using ITU-R P.526-12 to predict losses due to diffraction over the earth’s curvature, and the results obtained revealed that the model underestimated the RSS for the radio link. PubDate: 2022-11-10 Issue No:Vol. 14, No. 2 (2022)
Authors:Dharshini Devi Subramaniam, Soon Chong Johnson Lim Pages: 20 - 30 Abstract: Statistical process control (SPC) implementation plays a major role in quality assurance during the manufacturing process. Nevertheless, the adoption rate of SPC commercial software solutions is unsatisfactory in most Malaysian manufacturing companies due to high software subscription costs and difficulties in applying the software without proper know-how, guidance, and training. This study proposes the development of a purpose-built interactive data visualization web application for rapid SPC analysis in the manufacturing industry using open-sourced software packages. An agile software development model is applied as the software development methodology. In the requirement phase, an interview session was conducted to identify project requirements among stakeholders, i.e. industrial practitioners that are involved with SPC analysis. Based on the feedback and expectations from stakeholders, a design of a web application for SPC analysis that incorporates interactive parameter settings and automated reporting was proposed. The web application was developed using the R programming language and the Shiny package library, and deployed at ShinyApps.io, a web service provider. For evaluation, a usability testing procedure was designed and conducted with five industrial SPC practitioners to determine the usefulness of the web application. The outcome of the usability testing indicated positive results and feedback from evaluators. In conclusion, the developed web-app can assist users, particularly from the manufacturing industry sectors, to perform fast SPC data analytics, visualization, and reporting with ease. PubDate: 2022-11-10 Issue No:Vol. 14, No. 2 (2022)
Authors:Awang Mohd Ashraffarhan, Mohd Hazimin Mohd Salleh, Nur Shuhada Muhamad Tajudin Pages: 31 - 39 Abstract: The ecological concern over soil and groundwater pollution caused by agricultural activities has led to the growing interest in precision agriculture. One of the most common types of fertilizer is the nitrogen fertilizer which needed in major amount for plant growth. Over fertilization will contaminate soil and groundwater which can have adverse effect on environment and human health. The main purpose of this research is to measure soil nitrate concentration using nitrate ion-selective electrode (ISE) sensor and Arduino programmable microcontroller. The optimum soil-to-water ratio and the effect of soil solution clarity will be investigated. Standard sampling procedures was conducted at oil palm plantation area, Felda Bukit Goh, Pahang, Malaysia. Validation of the results were carried out in the laboratory. The recorded data indicated accurate readings for Nitrate ISE Arduino was R² = 0.84. The soil-to-water ratio of 1:2.5 was observed as an optimal proportion ISE analysis. A clear soil solution was crucial for maintaining the accuracy of ISE sensor, to avoid declining of 46.2% accuracy. These results could assist researchers and farmers to accurately monitor the concentrations of soil nitrate on the field effectively as well as an insight to ISE sensor with Arduino technologies. PubDate: 2022-11-10 Issue No:Vol. 14, No. 2 (2022)
Open Access journal
