LAUTECH Journal of Engineering and Technology (LAUJET)
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Effect of pretreatment and drying method on drying kinetics of ackee (blighia sapida) arils
Get PDFAckee (Blighia sapida) is a tropical fruit known for its nutritional content and health benefits, but its high perishable nature limits its shelf life. The research investigated the effect of different pretreatments and different drying methods on drying kinetics of ackee fruit arils. Freshly harvested ackee aril were portioned and subjected to pretreatments of blanching at 85 ? for 3 min, dipping in salt (NaCl) solution of 1, 2 and 3% w/v for 5 min and untreated samples served as control. The aril samples were dried at different temperatures (50, 60, 70 ?, solar and sun drying) monitored at intervals, until constant weight was obtained, and they were subsequently analyzed for drying kinetics, effective moisture diffusivity (Deff), activation energy (Ea), using standard methods. The drying was observed to take place in a falling rate period. The moisture content of the ackee aril before drying was found to be 62.847% wet basis and at the end of the drying experiment, the moisture content reduce to less than 3% in the dried samples. The moisture loss was at a fast rate in aril dried at 70 ? compared to 60 and 50 ? which could be due to an increase in the energy of water molecules with increased temperature resulting in quick evaporation of water from the sample. The effective moisture diffusivity (Deff) increased with increase in drying temperature from 50 to 70 ?. The overall highest effective moisture diffusivity was found to be 2.07 ×10-4 m2/s at oven drying temperature of 60 ?, 1% salt solution pretreatment, while the lowest was found to be 4.23 × 10-6 m2/s at oven drying temperature of 70 ?, 3% salt solution pretreatment. The activation energy obtained falls within the range of (106.10 – 125.29 kJmol-1) which indicates that the ackee aril processed is highly sensitive to temperature. The obtained drying data were fitted into five different thin layer drying mathematical models using coefficient of determination (R2), least values of Chi Square (?2), Root Mean Square Error (RMSE) and Mean Biased Error (MBE). Pretreatment had significant effect (p?0.05) on the drying of ackee arils. Midilli and Kucuk model described the drying behaviour of ackee aril pretreated with 1% salt (NaCl) solution and oven-dried at 70 ? satisfactorily having the R2 values of 0.999
An approach based on Firefly algorithm for optimal tuning of proportional-integral-derivative controllers for speed control of DC motor
Get PDFThis study presents an approach for optimal tuning of the parameters of PID controller for speed control of DC motor using Firefly Algorithm (FA) with the aim of delivering robust and accurate control of DC motors. Data for DC motor were sourced from Honey Well Flour Mills, Ilupeju, Lagos State, Nigeria, while its mathematical model was formulated using dynamic electric machine theory. MATLAB codes were written for the formulated model to simulate the open loop response of the motor. Ziegler-Nichols (ZN) method was initially used to design the PID controller and named ZN-PID, while a firefly algorithm tuned PID controller model was developed and named FA-PID. The performance of the FA-PID approach was carried out using rise time, setting time, mean squared error and overshoot as metrics. Simulation result indicate that at motor full speed, the rise time, settling time, overshoot and mean square error values for ZN-PID tuned controller were 0.5000, 6.196, 22.94 and 0.001415, respectively, as compared to 0.0051, 0.0081, 0.0002 and 0.000673 obtained using FA-PID tuned controller. The result revealed that FA is a potent optimization technique for optimal tuning of PID controller parameters; hence, the developed FA-PID tuned controller can be used by machine operators in various industrial applications for controlling the speed of DC motors
Investigating anomalous seepage trends in selected earth dams: a comprehensive study
Get PDFPrevious geotechnical reports established that the selected three dams, Igbeti, Awon, and Asa dams’ embankments are loosed and permeable and there is possibility of erosion within dam embankment. Geotechnical and seepage analyses of the earth dams were conducted to evaluate the dams’ safety against the leakages through the embankment dam.
Samples were collected at three different locations from the upstream and downstream sides of the dams, at depth of 600 mm using auger borer, and geotechnical tests were conducted on the samples, according to BS1377 of 1977 to determine the specific gravity (SG), sieve analysis, cohesion (C), angle of internal friction (?), coefficient of permeability (K), and natural moisture content (NMC). Steady- state analysis, using SEEP2D was employed to investigate the seepage flows within the dams, to simulate flow rates, pore pressure, velocity magnitude, hydraulic gradient, and seepage quantity.
Specific gravity values of the samples ranged from 2.36 to 2.79 (upstream) and 2.27- 2.75 (downstream). The particle sizes passing through sieve number 200 (0.002 mm) varied from 1.00 – 21.21% (upstream) and 0.58- 23.71% (downstream), while maximum dry densities are within the limiting values of 19- 23.5 kN/m2 (upstream) and 35.5 – 39.5 kN/m2 downstream. Permeability coefficients obtained varied averagely from 1.36 x 10-5 to 8.18x 10-4 at upstream and 9.32 x 10-6 to 4.45x 10-4 at downstream, and values obtained classified the soils as low- permeability, silty clay embankment materials. Natural moisture contents varied from 10.47% - 26.72% at upstream, 10.71%- 23.60% at downstream. Seepage analyses results for Igbeti, Awon and Asa dams were respectively: flow rates (3.9 x10-7 – 7.8 x10-7; 2.98x10-6 – 3.32x10-6; 6.00x10-6 – 6.60x10-6 m3/s); pore pressure (50000 – 16800; 60000 – 93000; 130000 – 185000 kN/m); velocity magnitude (0.0 – 0.000705; 7.93x10-11 - 6.30x10-6, 9.24x10-11 – 5.85x10-6 m/s).
The flow rates through the selected dams showed saturated embankments with the possibility of piping, and excessive leakage. Installation of internal drainage facilities such as sand filters, and toe gravel drains were recommended
Comparative analysis of score level fusion techniques in multi-biometric system
Get PDFMultimodal biometric systems have garnered significant interest from researchers owing to their applicability in security and access control. Despite the development of numerous score level fusion techniques for multimodal biometrics, most of them have concentrated solely on enhancing fusion accuracy, neglecting the potential advantages of various score level techniques. This research investigates the comparative performance of four different score level fusion approaches for multimodal recognition of combined face and fingerprints biometrics: Product rule, Weighted Sum rule, Simple Sum rule, and Max rule method. Five hundred and seventy (570) sample images from 190 students of Ladoke Akintola University of Technology (LAUTECH), Ogbomoso, used in this study were acquired using CMITech camera for faces and digital personnel for fingerprints, respectively. The images consist of three (3) samples of each biometric trait. Three hundred and forty-two (342) images of these traits were used for training while two hundred and twenty-eight (228) images were used for testing. The acquired images were pre-processed using histogram equalization, features extraction was done using Principal Component Analysis. Euclidian distance and Manhattan distance was used for generating the matching score of face and fingerprint feature respectively while Min-max was used to normalize each score. The fused score of each technique was used for identification. The results obtained was evaluated using False Acceptance Rate (FAR), False Rejection Rate (FRR) and Recognition Accuracy (RA) and Recognition Time (RT). Experimental results revealed that the Weighted Sum Rule outperformed other techniques, achieving a FAR of 1.75%, FRR of 5.85%, RA of 95.18%, and RT of 56.12 seconds. Comparatively, the Product Rule, Simple Sum Rule, and Max Rule demonstrated lower performance metrics. This study underscores the efficacy of the Weighted Sum Rule as a superior score-level fusion technique for developing advanced multimodal biometric systems, particularly in applications requiring high security and reliability
Quality evaluation of Gari from cassava substituted with blended Colocasia esculenta and Xanthosoma sagittifolium for enhanced food security
Get PDFThe increasing use of cassava for various products combined with its overreliance for gari processing, has created a volatile supply chain that results in skyrocketing gari prices, making the staple food unaffordable. The partial replacement of cassava with Colocasia esculenta and Xanthosoma sagittifolium can foster food diversification and security. The cassava and cocoyam tubers were processed into a mash and mixed at different substitution ratios (100:0, 90:10, 80:20, 70:30, 60:40, 50:50, and 0:100, w/w), fermented, dewatered, and roasted to produce gari samples. The gari samples were analysed for proximate, functional, antinutritional components, and sensory acceptability. The results have protein (1.02–4.61%), ash (0.75–2.57%), and fiber (2.02–2.20%) levels increasing as the proportion of cocoyam increased, while carbohydrate slightly decrease (82.33–88.25%). Physicochemical properties such as water absorption (2.07–4.57 g/g), swelling capacity (5.69–8.00%), and bulk density (0.46–0.59 g/ml) showed improvement across the various blends. The oxalate, tannin, and phytate were within acceptable thresholds. Sensory analysis showed that 80:20 cassava-to-cocoyam blend has highest overall acceptability score. This revealed the potential of cocoyam as a valuable yet underutilized ingredient that can enhance the production of gari and promote the diverse use of roots and tubers for sustainable food security
Wireless body fat measurement machine with a smartphone interface
Get PDFScientific literature and the World Health Organization (WHO) predict that in the year 2025, there will be about 2.3 billion adults globally who are overweight and 700 million who will be obese. This persistent metabolic disease has not been effectively addressed due to the use of inappropriate methods for measuring body fat and the unique characteristics of human physical and cellular structure. To ameliorate this condition, a new mechanism for weight measurement is proposed. The proposed mechanism operates with a minute alternating current (bioelectrical impedance technique) of 0.2– 0.8 mA via a two-lead finger. The device was designed with five components: 5 5-Volt Li-Po battery, a HC-05 Bluetooth module, a Dry electrode sensor, a Galvanic skin response sensor, and a programmable microcontroller (Arduino Shield) that is programmed to compute the voltage value for the body fat composition. The study was conducted within the University of Nigeria, Nsukka community, with adolescents aged 5 – 19 years for both genders and adults aged 20 – 38 years. The results revealed that as age (in years) and weight (in kg) increase, body fat percentage tends to increase. Weight in (kg) is a key parameter in the BMI method and was considered in the study, with consistent results as shown in the tables. To use the bioelectrical impedance technique, the approximated internal body resistance of 300 ? – 1 k?, age (in years), and weight (in kg) are necessary to obtain a precise body fat percentag
Blockchain Security Model for Minimizing Free-Riding in a Peer-to-Peer Network
Get PDFPeer-to-Peer (P2P) networks are unique innovations utilised in file sharing applications to accomplish better execution and evade a weak link. They can be centralised and decentralised, structured and unstructured. The prevalence of the P2P network has drawn in various attacks, including Free Riding, which decreases the adequacy of the network. Although numerous moderation strategies have been proposed to diminish the effect of such attacks, minimising free-riding is still a major challenge on the Internet. A P2P-based mechanism called blockchain technology is a promising tool capable of addressing this challenge due to its distinct features, such as transparency, provision of a highly secure platform, immunity to attackers, and cost-effectiveness. This research proposes a blockchain-based security structure for P2P networks to address free-riding and is modelled using an incentive approach. The proposed framework uses blockchain hash value to connect each peer with the associated super peer that grants an upload or a download, validating the peer and forming an immutable block in the network. The system was tested within a peer-to-peer file-sharing system simulation scenario and implemented using Java programming language. The simulation results show improved performance in identifying and countering free riders in the network with a fairness index of 0.8 to 0.9, blocking approximately 400 peers, and creating more than 4500 validated blocks at 2500 peers
Co- Digestion of Neem (Azadirachta indica) Shoot Biomass with Poultry Droppings: Effect of Pretreatment Methods on Biogas Production
No full textInadequate energy supply, environmental pollution, and declining soil fertility are major challenges in developing nations like Nigeria. Despite the abundance of biomass, much of it ends up as unmanaged solid waste. This study evaluated the effects of pretreatment on biogas yield from the co-digestion of Neem (Azadirachta indica) shoot biomass with poultry waste and cow rumen (inoculum). Materials were sourced from LAUTECH and prepared by washing, blending (mechanical pretreatment). The blended neem shoot was pretreated in a water bath to about 60 degrees Celsius for 1hr 20 minutes (thermal pretreatment). Chemical pretreatment was adopted to aid in the degradation of the lignin content. 4g of NaOH was dissolved in distilled water and then added to the thermally blended biomass. Two batches were prepared from the chemically treated Neem shoots, with poultry waste (batch A) and cow rumen (batch B), and put into airtight biodigesters. Physicochemical parameters (pH, TN, TP, TC, BOD, COD, MC, TS, C/N, FS) of both slurry and digestate were analyzed using standard methods. Biogas production, pH, and temperature were monitored over 30 days, and gas composition was determined via Gas Chromatography-Mass Spectrometry. Batch A showed biogas yields of 0.1016–0.0326 L/day, pH 8.39–8.41, and 35.7–35.8°C; Batch B yielded 0.1628–0.0488 L/day, pH 8.36–8.39, and 35.7–35.8°C. Methane content was 61.29% in Batch A and 63.29% in Batch B. ANOVA indicated significant differences in yields (p = 0.0256 for A, p = 0.0200 for B). Results showed that co-digestion, particularly with cow rumen, improved methane output. The produced methane is suitable for use in cooking, heating, and electricity generation, offering a sustainable solution for waste-to-energy conversion in Nigeria
Natural radionuclides distribution in quarry products from quarries in Osun and Oyo States, Southwestern Nigeria
Get PDFGranites are one of the major quarry products that are widely used in building materials, thus it is imperative to investigate its radiological safety as regard human protection. This study therefore determines the concentrations of natural radionuclides of 40K, 238U, and 232Th in quarry products of three different sizes (Stone-Dust, 3/4-Down and 3/4-Up) collected from quarries in Osun and Oyo States, Southwestern Nigeria, using gamma-ray spectrometry technique. The average radioactivity concentrations of 232Th, 238U, and 40K for Stone-Dust samples are 8.92 ± 0.81, 15.70 ± 1.19, and 374.26 ± 12.74, Bq/kg respectively while for 3/4-Up samples are 2.78 ± 0.39, 3.99 ± 0.65, and 146.99 ± 2.55, Bq/kg respectively and those for 3/4-Down samples are 5.68 ± 0.64, 6.61 ± 0.57, and 250.78 ± 4.02, Bq/kg respectively. The results of one-way analysis of variance (ANOVA-1) and Scheffee pair-wise comparisons tests performed on the quarry products showed that Stone-Dust samples have the highest mean activity concentrations, but all the analyzed samples have lower activity concentrations when compared with the recommended limits. This indicated that using the samples assayed for the mentioned purposes may not pose any radiological hazard to the workers and populace
Comparative analysis of SVM and logistic regression for classifying diagnostic microRNA signatures in colorectal cancer
Get PDFAbstract
The selection and classification of genes are critical for determining which ones are linked to a particular illness, especially cancer. As a result, it's critical to use machine learning algorithms to analyze relevant statistical data to aid biomedical researchers and end-users in the work of selection and classification. Few researches have been done on the early diagnosis of CRC using machine learning techniques to detect biomarkers, which are very important in colorectal cancer disease diagnoses. We therefore conduct a comprehensive gene selection and classification functionality using SVM and Logistic Regression algorithms on high-dimensional datasets. The results show that under the receiver operating characteristic (ROC) curve, the SVM and Logistic Regression models' discriminative capacities for classification were 83.5% and 73.2 %, respectively. This study thus reveals that the SVM algorithm outperforms the Logistic Regression algorithm in classifying data in the detection of Colorectal Cancer.
Keywords: Algorithm, Biomarkers, Classification, Colorectal Cancer, Disease Diagnosi