LAUTECH Journal of Engineering and Technology (LAUJET)
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Influence of ethanol on the spectral properties of natural dyes from microbes: implications for dye-sensitized solar cell performance
Get PDFThe increasing need for renewable energy sources that are both sustainable and less costly has spurred growing research into natural dyes as eco-friendly sensitizers for dye-sensitized solar cells (DSSCs). This study entails the extraction and characterization of natural pigments derived from Chlamydomonas starii and Coelastrella sp. focusing on solvent selection and thermal treatment. Ethanol proved much better than ethyl acetate and had the most remarkable effects on retaining functional groups, especially hydroxyl (O-H) and carbonyl (C=O), which would be important in terms of dye adsorption for improved photon absorption and electron injection. Spectroscopic analyses indicated that the ethanol-extracted dyes, especially non-heated and moderately heated ones, would enable a broad absorption of light within the visible spectrum. These findings hence have demonstrated that natural dyes extracted with ethanol were better than those extracted with ethyl acetate, which makes ethanol more efficient, scalable, and greener solvent for extraction of natural dyes compared to ethyl acetate. Future research is to focus on mixed solvent systems and stabilization techniques to improve dye performance even further. This will therefore be the greatest scion towards high-efficiency DSSCs while further supporting the global transition efforts toward sustainable energy technologies
Functional, physicochemical and pasting properties of pupuru and pupuru analogue made from cassava-orange fleshed sweet potato
Get PDFBlends of cassava (cas) and orange-fleshed sweet potato (ofsp) at the ratio of 75:25%, 50:50%, 25:75%, and 0:100% (cas: ofsp) respectively, and 100% cassava as the control were processed to pupuru flour. Samples were analyzed for functional properties, physicochemical properties and pasting properties. The packed bulk density and WAC ranged from 0.71-0.87, 0.79-0.93, 0.84-1.02, 0.95-1.06 g/ml; 2.01-4.05, 2.07-4.07, 2.04-3.12 and 2.07-3.15 g/ml at 75:25%, 50:50%, 25:75% and 0:100%, respectively. The pH ranged from 4.00-5.15, 3.63-4.12, 3.53-4.00 and 4.35-5.01 at 75:25%, 50:50%, 25:75%, and 0:100%, respectively. The cyanide contents ranged from 3.70-0.50, 3.40-0.42, 3.00-0.31, 0.27-2.97 and 1.31-4.40 at 75:25%, 50:50%, 25:75%, and 0:100%, respectively. The pasting time ranged from 4.60 -5.67 min, 4.20 -5.40 min, 4.30-5.50 min and 4.20 -5.50 min for the blended sample at 75:25%, 50:50%, 25:75%, and 0:100% (cas: ofsp), respectively. The pasting temperature ranged between 72.6-87.20 C, 66.4-85.50 C, 69.5-85.50 C and 65.5-81.50 C for 75:25%, 50:50%, 25:75%, and 0:100% (cas: ofsp), respectively. The final viscosity ranged from 1060-2645 RVU, 1368-2361 RVU, and 1268-2281, 1028-2081 for 75:25%, 50:50%, 25:75%, and 0:100% (cas: ofsp), respectively. This study has established the potentials of ofsp in the production of an acceptable nutrient densed pupuru to enhance food and nutrition security
Performance enhancement of amplify quantize and forward cooperative relaying technique in a wireless communication system: Performance enhancement of amplify quantize and forward cooperative relaying technique in a wireless communication system
No full textWireless communication systems are of paramount importance in the telecommunication infrastructure and have been playing a leading role in the development of nations. However, the system is characterized by multipath propagation effects that degrade the performance of the system. Amplify Quantize and Forward (AQF) cooperative relaying technique used to address the problem is characterized by poor performance due to signal amplification and obstruction along the propagating channel between the relay and destination. Hence, in this paper, the Enhancement of AQF (E-AQF) cooperative relaying protocol is carried out to improve the performance of the Conventional AQF (C-AQF) technique in a wireless communication system. The transmitted signal from the source is received at the relay node and the received signal is made to pass through spectral subtraction. The resultant signal is amplified using relay gain. The amplified signal at the relay node is quantized using uniform quantization before being forwarded to the destination during second hop transmission using angular beamforming. The multiple copies of the received signal at a varying path (L = 2, 4) are combined at the destination using Equal Gain Combiner (EGC). Mathematical expressions of Bit Error Rate (BER) and Throughput (TP) are derived using PDF. The performance of the proposed technique is evaluated using BER and TP by comparing it with the C-AQF cooperative relay technique. The proposed E-AQF gave better performance with reduced BER and increased TP than the C-AQF. The proposed E-AQF can be deployed to improve the performance of wireless communication systems
Enhanced chicken swarm optimization-tuned convolutional neural network for fingerprint-based ethnicity identification: Enhanced chicken swarm optimization-tuned convolutional neural network for fingerprint-based ethnicity identification
No full textIdentification of human being based on fingerprints have proven to be highly reliable. Researches have been done on fingerprint ethnicity identification, which are characterized with high false positive rate and high recognition time. This research developed Fingerprint Identification System with an enhanced CSO combined with CNN for better fingerprint ethnicity identification. One thousand two hundred (1200) subjects’ fingerprint images were acquired from three major ethnic groups in Nigeria (Yoruba, Igbo and Hausa) with equal ratio of male to female between the ages of 17–50 years, using Secugen Hamster Plus Fingerprint Scanner; Six hundred (600) acquired subjects’ fingerprints were augmented and used for training while the remaining 50% were used for testing. The raw images were pre-processed; CNN hyperparameters were tuned using CSO and CSO enhanced with Chaotic theory. The implementation was done using MATLAB R2023a software. The performance of the ICSO-CNN was evaluated and compare with CNN and CSO-CNN at a benchmark of 0.75 threshold value using, False Positive Rate (FPR) and Recognition Time (RT). The FPR and RT using CNN for Yoruba, Igbo and Hausa were 3.5% and 60.54s; 3.75% and 59.31s and 4% and 58.04s, respectively. The FPR and RT using CSO-CNN for Yoruba, Igbo and Hausa were 2.25% and 49.87s; 2.5% and 48.82s and 2% and 49.79s, respectively, while the corresponding values for the enhanced CSO-CNN were 1.75% and 36.64s, 2% and 38.56s and 1.5% and 39.35s. The developed fingerprint-based ethnicity identification system gave an improved identification performance over CNN and CSO-CNN. The developed ICSO-CNN can be used by security agencies for proper identification of criminals based on ethnicity
An Investigation of knowledge-based software defined networking framework for automation of wireless network resource management: An Investigation of knowledge-based software defined networking framework for automation of wireless network resource management
No full textWireless networks represent a significant portion of digital society, employing the packet-switched distributed architecture. Techniques such as deep learning-based traffic classification, reinforcement learning, mobile agents, and the identification of elephant and mice flows have been utilized to handle various network functions, such as traffic identification, routing strategies, and spectrum allocation. Software-defined Networks (SDN) have played a crucial role in addressing the challenges encountered in conventional network management. However, owing to the dynamic nature of networks and the high volume of network traffic, software-defined network architecture is insufficient to ensure optimal system performance in network environments. Hence, this research proposes a framework for integrating analytics and knowledge representation within a software-defined networking architecture, aiming to automatically optimize, diagnose, and troubleshoot wireless networks. A systematic literature review and qualitative comparative analysis were used to investigate knowledge-based Software-Defined Networking (SDN) architectural frameworks in the literature. The findings indicate the proposed framework outperformed other knowledge-based SDN frameworks in network functions and knowledge integration
Evaluation of the effect of slice thickness and drying temperature on selected characteristics of orange-fleshed sweet potatoes (Ipomoea batatas L.)
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Orange-Fleshed Sweet Potato (OFSP) is rich in beta-carotene, a precursor of vitamin A that combats Vitamin A Deficiency (VAD). Due to its high moisture content, drying is essential to extend shelf life, though high temperatures can degrade nutrients. This study examined the effects of slice thickness (2, 4, 6 mm) and drying temperatures (50, 60, 70? °C) on drying kinetics and quality of OFSP. Drying parameters such as Effective Moisture Diffusivity (Deff) and Activation Energy (Ea) were determined. Beta-carotene content and total colour change (?E) were evaluated. Drying data were fitted to six thin-layer models. Logarithmic model provided the best fit (R² = 0.999, ?² = 0.000 at 6 mm, 60? °C). Deff values ranged from 2.286×10?? to 3.195×10?? m²/s, and Ea ranged from 31.50 to 39.10 kJ/mol. The highest beta-carotene (29.12 mg/100 g) was retained at 6 mm, 50?°C, while the best colour (?E = 62.02) was at 4 mm, 60?°C. Overall, 4 mm slices offered a balance between drying efficiency and quality retention. Findings support optimized drying of OFSP to improve storage, nutrition, and food security, contributing to sustainable Development Goals (SDG) 1, 2, and 3
Pozzolanic Potential of Anacardium Occidentale Nutshell Ash (Aonsa) and Its Impact on the Mechanical Properties of Concrete
Get PDFInvestigating agricultural residue as pozzolans offers a two-fold benefits. It mitigates indiscriminate disposal what appears as a waste to some end users and promotes the sustainability of concrete. Tons of empty shells from Anacardium Occidentale Nutshells (AON), a by-product of the Anacardium Occidentale processing industry, are disposed indiscriminately in the environment where they eventually become nuisance. However, there is a notable paucity of all-inclusive studies exploring the pozzolanic potential and the impact of Anacardium Occidentale nutshell ash (AONSA) on the mechanical properties of concrete.
This study aims to contribute to the available knowledge base on the pozzolanic potential of AON being an agricultural residue, which serves as an outlet for AON. Mechanical properties of AONSA incorporated concrete was investigated. AONSA was obtained from the incineration of Anacardium Occidentale nutshell sourced from local Anacardium Occidentale processing unit in Ogbomoso and subjected to air-drying after getting rid of the nuts. Open ignition under ambient air took place to obtain AONS ash and this was calcinated in an Engineering Laboratory in LAUTECH.
AONSA samples A and B were placed differently inside furnace at 800 for 5 hours and 500 for 7 hours for calcination. X-Ray Diffraction (XRD) analysis and X-Ray Fluorescence (XRF) analysis and Scanning Electron Microscopy (SEM) analysis, were employed to assess the pozzolanicity of AONSA while notable observations of the effects of time and elevated temperatures on AONSA were noted.
The percentage XRD result of Quartz, Muscovite, Glauconite, Osumilite, Illite and Albite present in samples A and B are 6.4 (2), 47.8 (9), 18.3 (6), 23.6 (7), 3.9 (7), 0 and 24.3 (10), 21.3 (9), 29.9 (11), 0, 19.8 (9), 4.7 (2) respectively. XRF has these results for MgO, SiO2, P2O5, SO3, K2O, CaO, TiO2, MnO, Fe2O3, NiO, CuO, ZnO and Y2O3 for samples A and B are 7.620, 2.849, 4.761, 1.868, 20.88, 4.309, 583.5ppm,0.119, 10.073, 4.3 ppm, 388.9 ppm, 4.3 ppm, 388.9 ppm, 0.443, 75.0 and 5.691, 2.788, 4.817, 1.750, 21.893, 425.3 ppm, 0.115, 9.718, 0.0, 387.8 ppm, 0.851, 7.6 ppm, respectively. The element in SEM for samples A and B are K, Fe, Mg, Ca, P, Na, S, Si, Al, Cl, Ti with these percentages: 39.04, 12.24, 18.95, 6.81, 6.98, 6.93, 2.81, 3.02, 2.04, 1.18, 0.0 and 45.34, 7.28, 20.90, 5.93, 6.08, 6.27, 2.25, 2.48, 2.46, 1.01, 0.00, respectively.
The presence of silicate, lime, and aluminum oxides oxide in AONSA contributes to its suitability as a pozzolan. The SEM analysis shows that with increase temperature at 5 hours, the atomic weight of Potassium got reduced compared to decrease in temperature at 7 hours. The availability of SiO2 and Y2O3 in AONSA is essentially the same as that of cement. Furthermore, availability of MgO in AONSA is roughly 5.6912%, which is lower than 6% specified for cement in IS: 12, 269 – 1987. The amount of lime (CaO) in AONSA is roughly one-third that of Ordinary Portland Cement, as compared to alternative cement substitutes like fly ash
Synthesis and Characterization of Laggera Aurita-Derived Acetic Acid-Activated Carbon (LAAC) and it’s Potential for Toxic Element (TE) Metal Removal from Water
No full textThe increasing contamination of water resources by toxic heavy metals necessitates the development of cost-effective and sustainable adsorbents. This study investigates the synthesis, characterization, and adsorption potential of Laggera aurita-derived activated carbon (LAAC) for the removal of Pb(II), Cd(II), and Cu(II) from aqueous solutions. LAAC was prepared via acetic acid activation followed by pyrolysis at 500°C and characterized using FTIR, SEM, EDXRF, BET and XRD surface area analysis. FTIR confirmed the presence of functional groups (–OH, –COOH, –C?C–, and S–H) that facilitate toxic element (TE) adsorption through hydrogen bonding, ?-electron interactions, ion exchange, and chelation. SEM revealed a nanostructured surface (nanotubes and nanospheres) with high affinity for Pb²?, Cd²?, and Cr(VI) due to increased active sites. BET analysis indicated a microporous structure (334.6 m²/g), enhancing TE retention via ion trapping and complexation with –COOH/–OH groups. Horvath-Kawazoe (HK) analysis further demonstrated an ultramicropore volume (0.5939 cc/g), enabling molecular sieving and Pb²? capture through dehydration mechanisms. EDXRF revealed CaO, 5.334%, SiO?, 4.836%, CeO?, 5.009%, P?O?, 1.902%, and SO?, 2.2966%. CaO provides alkaline sites that enhance cation exchange for metals like Pb²?, Cd²?, and Cu²?. XRD confirmed the nanocrystalline nature (3.82 nm crystallite size), contributing to high surface reactivity. These findings highlight LAAC as a promising, sustainable adsorbent for heavy metal removal, with future research needed to optimize activation parameters and assess real-world applicability
Evaluation of the Environmental and Social Benefits of Conversion Process of Open Cycle to Combined Cycle Gas Power Plant
Get PDFWorldwide concern on reducing global warming consequences and combating energy crisis has motivated the development of power generation technologies to move towards sustainable energy production with higher efficiency and low environmental impacts. This study evaluated the environmental and social benefits of converting open cycle to combined cycle gas power plants in electric power generating system in Nigeria. All the current operational open and combined cycle gas power plants were considered. Green House Gas (GHG) emission data were collected for both open and combined cycle plants. The results showed that after conversion from open cycle to combined cycle, society bears a lesser cost of generating electricity as there is a minimum difference of 3.78 N/kWh (Calabar NIPP), which is about 23.34% change in cost and a maximum of 4.00 N/kWh (Omotosho Pacific Energy plant), which is about 25.20% change in cost for a minimum range of emission cost (40USD/tCO2e). There is a minimum difference of 8.54 N/kWh (Calabar NIPP), which is about 28.57% change in cost and a maximum of 8.76 N/kWh (Omotosho Pacific Energy plant) which is about 29.64% change in cost for a maximum emission cost (100USD/tCO2e). The study concluded that it costs less to reduce GHG and air pollution damage during the process of conversion from open cycle to combined cycle gas. Also, it is more beneficial to generate electricity using combined gas turbine and the society bears less cost for a higher electricity generation by a combined cycle when compared with an open cycle
Application of low-income agro-waste materials as filtration loss control agents in a water based drilling mud
No full textSaw dust (SD) and oil palm fruit waste (OPFW) were pretreated and pulverized accordingly, into particle sizes of <150µm and 150µm - 250µm range to serve as additives. Drilling mud was formulated based on standard procedure. Seventeen portions of the drilling mud were formulated having the first portion as a control with no additive. Four groups of each portion were made from the remaining 16 and additives were added with varying amounts ranging from 5g to 20g. Drilling mud properties were measured according to standard methods before and after addition of the additives and the performance of the materials were compared. Results showed that, with increasing amount of additives, filtration volume decreased while, mud cake increased. The results also showed that although, SD slightly outperformed OPFW only at lower particle sizes (<150µm), in terms of cake characteristics, fine and slippery mud cake formed with OPFW mud as opposed to the rough and hard cake obtained from the mud formulated with SD could also make OPFW more preferable. The study concluded that, due to the findings of this study, agro-waste materials, especially, SD and OPFW are veritable candidates for alternative loss circulation materials in drilling fluid