Research Articles

Permanent URI for this collectionhttps://atuspace.atu.edu.gh/handle/123456789/42

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A cloud-based Bi-directional LSTM approach to grid-connected solar PV energy forecasting for multi-energy systems
(Science Direct, 2023-12) Liu, Q., Darteh, O. F., Bilal, M., Huang, X., Attique, M., Liu, X., & Acakpovi, A.
The drive for smarter, greener, and more livable cities has led to research towards more effective solar energy forecasting techniques and their integration into traditional power systems. However, the availability of real-time data, data storage, and monitoring has become challenging. This research investigates a method based on Bi-directional LSTM (BDLSTM) neural network. BDLSTM takes into account the data’s past and future context. The future hidden layer takes input in ascending order while the past hidden layer evaluates the input in decreasing order, making BDLSTM relevant in analyzing the input data’s past context and evaluating future predictions. The eleven-year (2010–2020) weather dataset used for this paper was acquired from NASA. Two pre-processing approaches, Automatic Time Series Decomposition (ATSD) and Pearson correlation, were used to remove the noisy values from the residual components and for feature selection, respectively. To ensure storage and reuse of data, the architecture includes a cloud-based server for data management and reuse for future predictions. Popular in multi-energy systems, the cloud-based server also serves as a platform for monitoring predicted solar energy data. The metrics values and results obtained have demonstrated that the BDLSTM performs efficiently on the available data. Data from two separate climatic horizons proved the study’s quality and reliability.
Maximum power point tracking in power system control using reservoir computing
(Frontiers, 2022-02-24) Seddoh, M. A., Sackey, D. M., Acakpovi, A., Owusu-Manu, D. G., & Sowah, R. A.
Impact of energy efficiency and conservation programs on the national grid in some selected households in Ghana.
(Springer Nature Link, 2022-01-06) Acakpovi, A., Botwe-Ohenewaa, G., & Sackey, D. M.
This study evaluates the effect of energy efficiency and conservation on the Ghana National Grid. The motivation of this research study derives from the overwhelming lack of energy efficiency and conservation practices by consumers in Ghana while the existing generation continues to deplete with the increasing population and their growing energy needs. A survey was conducted on existing generation plants to assess their capacities and average power contributed to the national grid over a 6-month period. Energy efficiency and conservation awareness questionnaires was also administered to selected consumers to test their knowledge in energy efficiency and conservation. An energy audit and demand management program was established and implemented for a set of households, which were later audited, after a 3-month period to ascertain improvements in their energy consumption pattern. The study revealed that the implementation of energy efficiency and conservation measures led to a maximal reduction of energy consumed by 5.14% which is highly significant and subsequently led to positive economic and environmental implications. The study also found out that most of the respondents are unaware of energy efficiency and conservation measures; they make abusive use of non-efficient electrical appliances and do not implement any energy efficiency and conservation measures. The study recommended the development of policies and strategies to conduct mass education, to ensure the implementation of energy efficiency and conservation measures, and also to encourage the use of energy-efficient appliances. Successful implementation of the proposed recommendations contribute significantly to meeting the energy challenge in developing countries and subsequently sustain business while alleviating poverty.
An analytical model of diesel injector’s needle valve eccentric motion.
(International Journal of Engine Research, 2022) Wang, C.; Adams, M.; Jin, T.; Sun, Y.; Röll, A.; Luo, F.; Gavaises, M.
Past experimental studies have shown that the needle valve of high-pressure diesel injectors undergoes lateral movement and deformation, while the continuous increase in injection pressure enlarges the gap of the needle valve assembly. Two different analytical models, considering or omitting this change are presented here, linking the geometries of the needle valve assembly with the magnitude of needle valve tip lateral movement. It is found that the physical dimensions of the needle valve assembly and the injection pressure have a significant impact on the radial displacement of the needle. For example, for nominal clearances between the needle guidance and the needle valve of about 1–3 μm, the magnitude of the radial movement of the needle tip could reach tens of microns. The model that takes into account the variation of the gap between the needle guide and needle valve is found to give predictions closer to the experimental results.
Characterization of Al-5Ni-0.5 Mg/x (Al2O3-GNs) nanocomposites manufactured via hot pressing technique.
(Materials Characterization, 2022) Yehia, H. M.; Nyanor, P.; Daoush, W. M.
Exfoliating graphite to graphene nanosheets by mechanical ball milling with alumina, coating alumina particles with graphene layers to enhance their electrical and thermal properties, minimizing aluminum composite's production time, and improving the adhesion between the matrix and reinforcement were the aims of this study. Ball milling (BM) followed by electroless silver coating was used to prepare the (Al2O3-GNs) hybrid nanoparticles. A matrix sample from Al, 5 wt% Ni, and 0.5 wt% Mg was reinforced with different ratios of (Al2O3-GNs)/Ag nanoparticles up to 7.5 wt%. The cold and hot compaction technique was used to prepare the study samples. 550 °C and 50 min were the suitable parameters for fabricating the aluminum matrix composite. Microstructure investigation has been followed by chemical analysis, hardness, compressive strength, and electrical conductivity measurements. New intermetallic phases Al50Mg48Ni2, AlNi, and AlMg, have been formed during the powder consolidation by the hot-pressing process. The density of the Al-5Ni-0.5Mg (3.005 g/cm3) matrix was not significantly affected by the Al2O3/GN (3.907 g/cm3) reinforcement density. The 7.5 wt% Al2O3-GN reinforced composite exhibits the highest hardness. The electrical conductivity and the composites' compressive strength are also increased by 133% and 78%, respectively, for the 7.5 wt% sample.
Self-Formed Diffusion Layer in Cu (Re) Alloy Film for Barrierless Copper
(Coatings, 2022) Cheng, B.; Chen, H.; Asempah, I.; Wang, J.; Zhu, Y.; Wan, J.; Qiao, Y.
The barrier properties and diffusion behavior of Cu(Re) alloy films were studied. The films were deposited onto barrierless SiO2/Si by magnetron sputtering. X-ray diffraction patterns and electric resistivity results proved that the Cu(Re) alloy films without a barrier layer were thermally stable up to 550 °C. Transmission electron microscopy images and energy-dispersive spectrometry employing scanning transmission electron microscopy provided evidence for a self-formed Re-enriched diffusion layer between the Cu(Re) alloy and SiO2/Si substrate. Furthermore, the chemical states of Re atoms at the Cu(Re)/SiO2 interface were analyzed by X-ray photoemission spectroscopy. The self-formed diffusion layer was found to be composed of Re metal, ReO, ReO2 and ReO3. At 650 °C, the Cu(Re) layer was completely destroyed due to atom diffusion. The low electrical resistivity in combination with the high thermal stability suggests that the Cu(Re) alloy could be the ultimate Cu interconnect diffusion barrier.
Hydrothermal fabrication of MoS2/reduced graphene oxide nanohybrid composite for the electrochemical sensing of Hg (II) in green tea.
(Materials Today: Proceedings, 2022) Annavaram, V.; Somala, A. R.; Chen, Q.; Kutsanedzie, F. Y.; Agyekum, A. A.; Zareef, M.; Hassan, M. M.
Heavy metal contamination is a standout among the most genuine ecological issues: toxicity, persistence, bioaccumulation, and biomagnification through food chains. The present work aims at the synthesis of abundant, fast-sensing electrochemical sensors MoS2 and MoS2@rGO composite by the hydrothermal method to develop electrochemical sensors for the detection of Mercury (Hg-II). The synthesized material was characterized and conformed to a hierarchical spherical sponge-like structure with a high surface-to-volume ratio. The electrochemical sensor conditions were observed at ambient conditions to detect Hg (II) (0.5, 1, 1.5, 2, 2.5, 3, 3.5 µm L−1 was used) and the results showed very promisingly. The limit of detection (LOD) was found to be 2.0 × 10−7 µg/mL for MoS2, 1.22 × 10−8 µg/mL for composite. The heavy metals were spiked in green tea extract to observe the sensor ability of the material. The sensor ability for the material for real-time detection of green tea was found to be LOD-2.12 × 10−7 µg/mL (MoS2) and 1.21 × 10−9 µg/mL (MoS2@rGO).
Rapid Detection and Prediction of Norfloxacin in Fish Using Bimetallic Au@ Ag Nano-Based SERS Sensor Coupled Multivariate Calibration.
(Food Analytical Methods, 2022) Agyekum, A. A.; Kutsanedzie, F. Y.; Mintah, B. K.; Annavaram, V.; Braimah, A. O.
Norfloxacin is an antibiotic in the fluoroquinolone family licenced for use in animals. However, residues in animal products can have negative consequences for consumers. As a result, residue detection in various food matrices must be considered. Norfloxacin accumulates in animal-derived foods, causing deleterious consequences in humans such as foetal deformity, renal failure and drug resistance. A built-in SERS-Au@Ag nanosensor coupled with GA-PLS was used to rapidly detect norfloxacin in the specimen of the spiked fish muscles due to the threat to human lives. A detection limit of 2.36 × 10⁻⁵ μg/mL was realized in the spiked fish muscle sample for norfloxacin compared to the European Commission’s maximum threshold level of 100 μg/kg, indicating the sensor’s ability to detect and quantify norfloxacin at a relatively lower level. The recovery rates (RC) and coefficient of variation (CV) measured in the spiked fish muscle samples for norfloxacin analytes and their standard solutions were between 99.70–105.00% and 0.17–5.21%, respectively. The low CV values imply the reproducibility of the obtained data. The constructed model recorded residual predictive deviations (RPD) greater than three (3), demonstrating the robustness and resilience of the developed genetic algorithm-partial least squares (GA-PLS) model. GA-PLS-built models predicted all results within 4.07 s, which indicates the nanosensor’s ability to rapidly detect norfloxacin in fish to guarantee safety and public health. The SERS probe holds promise for rapid quantification of norfloxacin at microgram per milliliter level in fish to guarantee safety in commerce.
Staple food fortification for malnourished children and pregnant women in Northern Ghana.
(International Journal of Engineering Research, 2016) Okwabi, R.; Sampare, S. A.
Most people in rural Africa and other developing countries take in food that is not sufficiently rich in nutrient. The reason for this deficiency is because of poverty, specifically lack of money to buy proper dietary food or ignorant in consuming the right nutritional food is of concerned. This phenomenon had led to many health problems such as anemia, night blindness, high maternal mortality rate, brain damage and the rest. Many people in Northern Ghana are deficient in micro-nutrient intake, particularly children and pregnant women. The quickest and cost effective way is through the fortification process. The White maize flour which is the staple food for people living in Northern Ghana can be increased by missing with a premix (Super cereal Plus). The fortification process was carried with a low cost technology of Hand Operated Mixer Machine. A 0.0175:50 kg premix-white maize flour was estimated to be the standard nutrition needed by malnourished children and pregnant women. Homogeneous of the food fortification was achieved with the Hand Operated Mixer Machine, however, attention must be given on modification of the machine, particularly for ease of operation and at a lower cost.
Determining the level of knowledge of lean production techniques in newspaper firms in Ghana.
(International Journal of Engineering Research & Technology (IJERT), 2016) Govi, D.K.; Amoakoh, C. N.; Goddey, P.G.
Many people, especially the youth, are also turning to the internet for news at the expense of Newspapers. Financial viability for newspapers, at least for now, requires retaining as many existing print readers as possible. However, as trend for Newspaper circulation shows a continuous decline over the past decade, publishers need to ensure that production waste is reduced to the barest minimum to keep costs down so as to remain afloat. The newspaper business has trived on high advertising revenue for decades until now that they are confronted with the Internet and new media. The study will critically examine the existing production system, including systematic work flow and ascertain the possibilities to identify and eliminate the perceived waste in the production chain. This critical assessment will be carry out using appropriate statistical tool to reveal the consequential impacts of such waste in the production system.
The use of lean thinking in managing productivity; a case of crystal-clear filtered drinking water.
(International Journal of Engineering Trends and Technology (IJETT), 2016) Govi, D. K.; Nyanor, P.; Deku, A.
Design and construction of drain covers to mitigate flood in the cities
(International Journal of Science and Research (IJSR), 2017) Oman, E. K.; Okwabi, R.
Abstract: Flood in Ghana is growing from bad to worse. Many Ghanaians for the past years have lost their lives and properties, and other displaced from their homes through flood. The main course attributed to the flood is choke drainage system. Observation shows that the city’s roads have been encroached by settlers and food venders who through all sort of waste into the drainage system through the drain covers. Mud pickup by vehicles are also drop on the roads and washed by rain into the drainage system. Approximately 59 of the drain covers have been stolen. In order to overcome these challenges a drain cover was design and constructed for experiment. The experimental results taken after experimenting on the drain cover shows that flood mitigation is possible as 77% mud was trapped by the drain cover when liquid-solid waste mixture was pass through it. However, recommendation was made to further improve on the drain cover to overcome the passing of heavy vehicles.
Effective heat transfer design for solid and cavity wall configuration.
(Recent Advances in Petrochemical Science, 2017) Amenyah, W.; Govi, D.K.; Acakpovi, A.
This paper seeks to outline good practice in the design, installation and operation of building cooling systems. It encompasses the discussion on the different types of cooling systems that must be applied for particular needs. The paper also deals with the philosophy of building heat gain, the methodology in the prediction of cooling load energy and ultimately the importance of optimizing heat transfer. In the methodology section, Fourier’s law was used to design the cooling systems for a solid wall and a cavity wall of same area made from material of similar heat transfer coefficient. Results showed that the cavity wall permitted less heat transfer into the confined space hence less electricity required to cool it. It is recommended therefore that, large public buildings should be designed in this manner so as to reduce the need for unnecessary electrical power to maintain them.
Investigation of pulse electrochemical sawing machining of micro-inner annular groove on metallic tube
(International Journal of Machine Tools and Manufacture, 2016) Liu, G. X.; Zhang, Y. J.; Jiang, S. Z.; Liu, J. W.; Gyimah, G. K.; Luo, H. P.
Pulse electrochemical sawing micro-machining (PECSM) is a non-conventional process. Having features of no tool wear, no cutting force, and good surface quality, this process is suitable for machining micro-grooves on the inner wall of hole. The rotating dentate cathode (RDC) is beneficial for the distribution of electrolyte and electrolytic products removal, thus reducing the effects of concentration polarization on the electrochemical reaction. This study focuses on the PECSM of micro-inner annular groove on 304 stainless steel tube using a pH-neutral NaClO3 electrolyte. To study the effects of RDC on the process, the bubble layer structure (BLS) adhered to the surface of RDC was photographed using a high-speed camera. Under the condition of immersion, the symmetric distribution of two kinds of BLS adhered to the RDC surface. The four selected parameters (radius of dentate cathode, rotational speed of RDC, initial gap, feed rate) with different levels were carried out to study the process of PECSM micro-inner annular grooves on 304 stainless steel tube. Experimental results indicate that PECSM has high potential for machining micro-inner annular groove on metallic tube. A micro-inner annular groove that is 340 μm in depth and 263 μm in width was fabricated on a 304 stainless steel tube.
Feasibility study on nondestructively sensing meat's freshness using light scattering imaging technique.
(Meat Science, 2016) Li, H.; Sun, X.; Pan, W.; Kutsanedzie, F. Y.; Zhao, J.; Chen, Q.
Rich nutrient matrix meat is the first-choice source of animal protein for many people all over the world, but it is also highly susceptible to spoilage due to chemical and microbiological activities. In this work, we attempted the feasibility study of rapidly and nondestructively sensing meat's freshness using a light scattering technique. First, we developed the light scattering system for image acquisition. Next, texture analysis was used for extracting characteristic variables from the region of interest (ROI) of a scattering image. Finally, a novel classification algorithm adaptive boosting orthogonal linear discriminant analysis (AdaBoost–OLDA) was proposed for modeling, and compared with two classical classification algorithms linear discriminant analysis (LDA) and support vector machine (SVM). Experimental results showed that classification results by AdaBoost–OLDA algorithm are superior to LDA and SVM algorithms, and eventually achieved 100% classification rate in the calibration and prediction sets. This work demonstrates that the developed light scattering technique has the potential in noninvasively sensing meat's freshness.
Quantifying total viable count in pork meat using combined hyperspectral imaging and artificial olfaction techniques.
(Food Analytical Methods, 2016) Li, H.; Kutsanedzie, F. Y.; Zhao, J.; Chen, Q.
Total viable count (TVC) of bacteria is one of the most important indexes in evaluation of quality and safety of meat. This study attempts to quantify the TVC content in pork by combining two nondestructive sensing tools of hyperspectral imaging (HSI) and artificial olfaction system based on the colorimetric sensor array. First, data were acquired using HSI system and colorimetric sensors array, respectively. Then, the individual characteristic variables were extracted from each sensor. Next, principal component analysis (PCA) was used to achieve data fusion based on these characteristic variables from two different sensor data for further multivariate analysis. In developing the models, linear (PLS and stepwise MLR) and nonlinear (BPANN and SVMR) pattern recognition methods were comparatively employed, and they were optimized by cross-validation. Compared with other models, the SVMR model achieved the best result, and the optimum results were achieved with the root mean square error of prediction (RMSEP) = 2.9913 and the determination coefficient (R p ) = 0.9055 in the prediction set. The overall results showed that it has the potential in nondestructive detection of TVC content in pork meat by integrating two nondestructive sensing tools of HSI and colorimetric sensors with SVMR pattern recognition tool.
Harmonic analysis of cavitation in engine cooling fluid due to piston-cylinder assembly forces.
(Procedia Manufacturing, 2017) Deku, A.; Nyanor, P.
The problem with cavitation and possible pitting in internal combustion diesel engines is studied here. Both theoretical and numerical simulation studies are carried out in order to understand the noise and vibration sources using a force equation. Noise and vibration are modeled in both 2D and 3D using the finite element analysis software ANSYS. A model pressure variation is carried out using the software with finite element analysis and fluid – structure interaction analysis interface. Some relevant results have been shown with the presence of negative pressures leading to the realization that the models developed predicts the presence of cavitation in the cylinder liner surface, indicating that cavitation can occur.
Application of powder metallurgy methods for production of a novel Cu-based composite frictional train brake material.
(Powder metallurgy-fundamentals and case studies, 2017) Gyimah, G. K.; Guo, Z.; Huang, P.; Chen, D.
A novel Cu-based composite frictional train brake material composed of several elements such as Al, SiO2, Fe, graphite, Sn, Mn and SiO2 re-enforced with other elements was treated under Powder Metallurgy (P/M) route. The materials were sintered at three different temperatures (850°C, 900°C and 950°C) at a constant pressure.
A rapid one-step process for fabrication of biomimetic superhydrophobic surfaces by pulse electrodeposition.
(Materials, 2017) Jiang, S.; Guo, Z.; Liu, G.; Gyimah, G. K.; Li, X.; Dong, H
Inspired by some typical plants such as lotus leaves, superhydrophobic surfaces are commonly prepared by a combination of low surface energy materials and hierarchical micro/nano structures. In this work, superhydrophobic surfaces on copper substrates were prepared by a rapid, facile one-step pulse electrodepositing process, with different duty ratios in an electrolyte containing lanthanum chloride (LaCl3·6H2O), myristic acid (CH3(CH2)12COOH), and ethanol. The equivalent electrolytic time was only 10 min. The surface morphology, chemical composition and superhydrophobic property of the pulse electrodeposited surfaces were fully investigated with SEM, EDX, XRD, contact angle meter and time-lapse photographs of water droplets bouncing method. The results show that the as-prepared surfaces have micro/nano dual scale structures mainly consisting of La[CH3(CH2)12COO]3 crystals. The maximum water contact angle (WCA) is about 160.9°, and the corresponding sliding angle is about 5°. This method is time-saving and can be easily extended to other conductive materials, having a great potential for future applications.
Comparative study of flow characteristics within asymmetric multi hole VCO and SAC nozzles.
(Conversion and Management, 2017) Adams, M.; Zhou, Q.; Xue, F.; Luo, F.
A three-dimension model of an asymmetric valve covered orifice (VCO) nozzle and an asymmetric blind hole nozzle (SAC) used in two valve engines were developed for investigating in-orifice flow characteristics. Two fluid model approach used for turbulence and cavitation modeling was used to replicate the turbulence and cavitation phenomenon within the nozzles. The formation and the subsequent development of cavitation phenomenon was comparatively more prevalent in the VCO nozzle orifices. Cavitation development intensity was observed to be more significantly influenced by orifice inclination angles in the VCO nozzle as compared to the SAC. Although in-orifice flow velocity of VCO are higher under cavitating condition, their corresponding injection rates are lower comparatively, due to the formation of smaller effective flow areas in the orifices. However under non-cavitating condition, the in-orifice flow velocities and effective injection velocities from the SAC orifices are higher, relative to that from the VCO. The cavitation phenomenal distribution within the SAC orifices were at the top areas while that of the VCO were mostly at the mid-sections of the orifices. Increasing orifice inclination angle increases the degree of cavitation phenomenon but decreases the uniformity of in-orifice flow velocity in the nozzles. The rate of non-uniformity in orifice flow velocity distribution is much higher within the VCO orifices as compared to the orifices in the SAC. With a comprehensive insight of in-orifice nozzle flow characteristics for asymmetric nozzles, the combustion efficiency and the rate of soot formation in a two valve engine can be managed and improve significantly by manufacturers.

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