Nigerian Journal of Technology最新文献

{"title":"Effect of cellulosic micro- and nano- sized fillers on strength and microstructure of rubber composites","authors":"J. O. Oboh, Kingsley Kema Ajekwene, A. Okele, S. I. Ichetaonye, I. B. Mohammed","doi":"10.4314/njt.v43i2.12","DOIUrl":"https://doi.org/10.4314/njt.v43i2.12","url":null,"abstract":"The tensile strength of polymer composites is basically influenced by the geometry (size and shape) of the reinforcing material as well as interfacial interaction and bonding between the polymer matrix and reinforcing phase. This work compares the effect of microfillers to nanofillers of coconut husk, bamboo and cotton linter on the tensile strength and microstructure of vulcanized rubber matrix. The various composites were formulated and prepared using filler loading of 5, 10, 15, 20, 25 and 30 parts per hundred of rubber (pphr) in rubber matrix for both micro- and nano- fillers of the various biomass through friction shearing and compression moulding processes. Results revealed that the tensile strength of the nanocomposites predominantly increased from 1.85 MPa for neat sample to maximum values of 3.83, 3.16 and 3.85 MPa respectively for composites with 25pphr of coconut husk cellulosic nanoparticles (NR-CHNC25), 30pphr of bamboo cellulosic nanoparticles (NR-BNC30) and with 25pphr of cotton linter cellulosic nanoparticles (NR-CLNC25) conversely, the tensile strength of their counter microcomposites changes from 1.85MPa for neat sample to maximum values of 1.68, 1.67 and 2.46 MPa for composites with 10pphr of coconut cellulosic microparticles (NR-CHMC10) 15pphr of bamboo cellulosic microparticles (NR-BMC15) and 30pphr of cotton linter cellulosic microparticles (NR-CLMC30) respectively within the loading range employed in this experiment. Scanning Electron Microscope (SEM) images of microcomposites showed cases of microfiller debonding and pull-out from the rubber matrix. Hence the improved tensile strength of nanocomposites over their counterpart microcomposites was attributed to the larger surface area provided by nanofillers for interfacial bonding and effective stress transfer.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"124 44","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141820875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of building deformation monitoring using stereophotogrammetry method and Kalman filter model","authors":"A. Alademomi, O. A. Jimoh, E. E. Atojunere, A. O. Alabi, S. A. Ishola, I. V. Ayantayo-Ojo, T. J. Salami, J. O. Odumosu, Chidozie Charles","doi":"10.4314/njt.v43i2.5","DOIUrl":"https://doi.org/10.4314/njt.v43i2.5","url":null,"abstract":"This research investigates building deformation monitoring using stereophotogrammetry and integrating the Kalman filter to refine the result with conventional geodetic measurements being the baseline. By refining stereophotogrammetric coordinates with the Kalman filter, the study aims to improve measurement precision in the detection of displacement which is a measure of differences in converted stereo-coordinates obtained from the observed points over time. The refined coordinates exhibited higher accuracy compared to raw stereophotogrammetric measurements, highlighting the effectiveness of the proposed approach in reducing observational errors and relatively detected and quantified building deformations with an average rate of displacement of 0.025978169 m/epoch in the x-axis, 0.030498323 m/epoch in the y-axis, and 0.014078842 m/epoch in the z-direction, and a range of 0.000155 m/epoch to 0.593497 m/epoch. Points P03 (0.008 m/epoch), PH04 (0.021 m/epoch), and PH22 (0.037 m/epoch) on the monitored building indicated the highest displacement. This research contributes to the field of knowledge in the area of deformation monitoring by offering an innovative methodology for accurate assessment of building deformation. In the overview, this research demonstrates the potential of a simple, efficient, and cost-effective method of monitoring deformation that can ensure the safety and sustainability of engineering structures.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"111 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141822662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of coarse aggregate grading types on the cost of concrete","authors":"C. U. Anya, I. C. Onyechere, J. I. Chukwu, N. L. Nwakwasi, F. C. Njoku, O. Ani","doi":"10.4314/njt.v43i2.4","DOIUrl":"https://doi.org/10.4314/njt.v43i2.4","url":null,"abstract":"The effects of grades of coarse aggregates on the cost of concrete was studied. Several times in real life practice, the engineer at construction site is faced with the problem of not having the required grade of coarse aggregate for a given project. . This could be caused by several reasons such as; non-availability of desired grade, the different grades of coarse aggregate being obtained as a left over from a sister project, etc. In Nigeria, coarse aggregate for concrete is very expensive and thus, the engineer will think of how to use the available grade of coarse aggregate in his concrete mix design to achieve the desired results instead of discarding it. In this study, seven different grades of coarse aggregate were investigated. The fineness modulus of the fine aggregate and bulk densities of the various grades of coarse aggregate were determined. The results were used together with tables from American Concrete Institute (ACI) code to carry out concrete mix design on all the various grades of coarse aggregate to calculate the quantities of the different elements of concrete. From the mix design, the cost of the materials for producing one cubic meter of concrete was determined. The result showed that the Well graded aggregate had the highest bulk density of 1717Kg/m3 while uniformly graded retained on 10mm sieve had the least bulk density of 1580Kg/m3. Uniformly graded aggregate retained on 10mm sieve required the highest cost of N58,278.81 to produce a cubic meter of grade 25 concrete while the cost was least at N56,242.52 when uniformly graded retained on 20mm sieve and Gap-graded without 5mm size were used. This suggests that the larger the size of coarse aggregate (within the size limits studied) the less the cement paste required and hence the less the cost.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":" 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141822927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polymeric microneedle arrays for transdermal rapid diagnostic tests and drug delivery: a review","authors":"I. V. Diwe, H. Mgbemere, O. A. Adeleye, I. Ekpe","doi":"10.4314/njt.v43i2.11","DOIUrl":"https://doi.org/10.4314/njt.v43i2.11","url":null,"abstract":"In recent times, the demand for innovative, insignificantly invasive diagnostic and therapeutic biomedical tools has reached enhanced attention. Rapid Diagnostic Tests (RDTs) for diagnosis, which are non-invasive, inexpensive, simple, and deliver results accurately in less than 20 minutes, have heightened the accessibility to parasite-based analysis globally. Microneedle (MN) arrays are a fast-developing and promising technology for drug delivery and extraction of Interstitial fluid (ISF) employed for numerous diagnostic and clinical therapies. This review gives a broad overview of the characteristics and history of Microneedles (MNs) patches together with their applications in drug delivery and transdermal rapid diagnostic purposes, classifications, and categories based on the design of fabrication from previous works of literature spanning the period 2018-2023. Utilizing PubMed, Scopus, Google Scholar, and Wiley online library search engines, an online search for scientific publications published between 2018 and 2023 was conducted using the keywords \"microneedle patch\" and \"rapid diagnostic tests.\" 175 articles in all were found when the search terms were used. The acquired results were then narrowed to 64 citations in this review by applying the inclusion principle. Pictorial and tabular representations highlight the various features of Microneedle patches used in interstitial fluid testing and extraction that have been documented experimentally, including numerous applications of Microneedle patches, showing their dimensions, applications, fabrication methods, and findings made. Finally, research on bio-microneedles and bio-inspired MN are reviewed. The research findings indicate that dissolving microneedles has become increasingly popular since they have several benefits over other microneedles. It is among the most well-known microneedles, and since it degrades naturally, it is a superior option for diagnosis and long-term treatment.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"113 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141821307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of split tensile strength of concrete using basalt and granite as coarse aggregates","authors":"F. Idagu, D. O. Onwuka, C. Okere, U. S. Onwuka","doi":"10.4314/njt.v43i2.7","DOIUrl":"https://doi.org/10.4314/njt.v43i2.7","url":null,"abstract":"This work aims at comparing the splitting tensile strength of basalt concrete mix with granite concrete mix. A total of 24 cylindrical concrete specimens of diameter 100mm and length 200mm were made in the laboratory. The British standard mix design method was used to obtain four different mix designs for batching the ingredients comprising ordinary Portland cement, river sand, water, granite and basalt with two mix designs each corresponding to basalt and granite samples. The specimens were cured for 28 days and tested for splitting tensile strength. The results show equivalent values of splitting tensile strength for basalt and granite samples with values for granite samples slightly higher than those of basalt samples. The average splitting tensile strength of the basalt samples B1, B2, B3, B4, B5 and B6 are 11.10 N/mm2, 10.37 N/mm2, 11.37 N/mm2, 10.13 N/mm2, 11.60 N/mm2, 10.25N/mm2 respectively while that of the granite samples G1 and G2 are 11.52 N/mm2 and 10.58N/mm2 respectively. The corresponding mix ratios are 1:1.96:2.81 for B1, B3, and B5 samples, 1:2.25:2.75 for B2, B4, and B6 samples, 1:1.80:2.75 for G1 sample and 1:2.07:2.76 for G2 sample.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"122 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141822189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Single topology neural network-based voltage collapse prediction of developing power systems","authors":"J. N. Onah, C. O. Omeje, D. Onyishi, J. Oluwadurotimi","doi":"10.4314/njt.v43i2.14","DOIUrl":"https://doi.org/10.4314/njt.v43i2.14","url":null,"abstract":"Most modern power systems operate within the vicinity of saddle-node bifurcation points because the network operators are hard put to estimating the margin to voltage collapse before the blackout. As a result, voltage stability analysis and control are growing concerns amongst electric power utilities. The selection of the hidden layer units and the training function algorithms for back propagation artificial neural network training are major challenges. Hitherto, comparative analyses of the training functions were made. Thereafter, the complexity of the artificial neural network topology was made very simple by selecting the hidden layer neurons via scripts written in Matlab software environment. To obtain the hidden layer unit, a script has to be developed in MATLAB to select a hidden layer neuron from a range of 10 to 65. The result shows that the optimal 55 hidden units have root mean square error (RMSE) of 0.05. The result was validated when the range of hidden layer neurons was extended to 100. The proposed approach was tested in a typical developing power system: a 45-bus Nigerian 330kV transmission network and proved to be fast and accurate for voltage collapse prediction.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":" 1117","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141823248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microcontroller-based facts devices implementation","authors":"V. C. Madueme, A. O. Ekwue, E. C. Ejiogu, V. O. Ajah","doi":"10.4314/njt.v43i2.19","DOIUrl":"https://doi.org/10.4314/njt.v43i2.19","url":null,"abstract":"In power systems, the case of voltage control, power factor improvement and reactive power management cannot be over-emphasized. In developing countries such as Nigeria, the electricity power system is characterized by operational constraints which are predominantly poor power quality, voltage fluctuations and increased power losses among others. Furthermore, these frequent system disturbances contribute to the unreliability of such power system. This paper looks at the thyristor-switched capacitor- thyristor-controlled reactor (TSC-TCR), static volt-ampere-reactive controller (SVC), a flexible alternating current transmission system (FACTS) device as a solution to mitigate the thermal and voltage problems associated with the Nigerian network. A microcontroller-based SVC prototype was designed in Proteus software and implemented in a laboratory environment using locally available discrete electronic components for load power factor correction based on distributed reactive power control. The microcontroller was in charge of carrying out the logic control scheme for the two branches and computing the load displacement power factor (PFD). The SVC was found to improve the PFD by 44.78% under inductive loading where the power factor increased significantly from 0.67 to 0.97.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"101 35","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141821100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Process capacity improvement by equipment and operations control ratios in de-husking lines of small-scale rice processing factories","authors":"C. Achebe, S. Nwanya, S. O. Enibe","doi":"10.4314/njt.v43i2.8","DOIUrl":"https://doi.org/10.4314/njt.v43i2.8","url":null,"abstract":"Inadequate knowledge of equipment and operations control ratios which contribute largely to low process capacity in the de-husking lines of small-scale rice processing factories is one of the critical challenges to improving rice processing in Sub-Saharan African countries, particularly Nigeria where capacity deficit leads to rice importation. This study seeks to empirically investigate equipment and operations control ratios in de-husking lines of small-scale factories in order to explore their potential and improve process capacity. The objectives are to determine the equipment and operations effectiveness, identify the root causes of inefficiency, and prioritize improvement efforts in the de-husking lines. The study was carried out in 10 selected factories of a milling cluster where production data for 2017-2022 was collected to complement data obtained through direct observation during processing hours and structured interviews. Microsoft Excel and Scilab software were used for data analysis based on existing models and other mathematical models developed for this study. Fluctuations observed in the process capacities of the de-husking lines from 2017-2022 indicated variabilities in equipment availability and performance. The overall equipment effectiveness (OEE) was generally below 50% which indicates production losses caused by frequent downtime and reduced speed of the machines. The overall operations effectiveness (OOE) were below 40%, and that implies the de-husking lines do not respond well to unscheduled downtime or unexpected tasks to reduce downtime for process capacity improvement. Tracing other potential to be unlocked to improve process capacity with the existing machines in the de-husking lines; the total effective equipment performance (TEEP) values were found below 25%, leaving 75% potential to be unlocked. Reliability modelling before machine installation, preventive maintenance, extended work scheduling, continuous training of workforce to reduce delays in equipment repairs are some of the measures to increase machine availability and improve process capacity in de-husking lines of small-scale rice processing factories.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"123 43","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141821732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and modeling of a proportional derivative controller for a three-phase induction motor speed","authors":"C. A. Ekim, I. O. Akwukwaegbu, E. Ubom, U. S. Ukommi, C. O. Jude-kennedy, C. K. Joe-Uzuegbu, O. Ani","doi":"10.4314/njt.v43i2.17","DOIUrl":"https://doi.org/10.4314/njt.v43i2.17","url":null,"abstract":"Many applications require variable speed operation. The motor speed needs to be controlled to save more power. It became highly imperative for further research to find out an efficient method that can yield an optimal speed control. This study presents the design and modeling of a proportional derivative controller for a three-phase induction motor speed control. The scalar control methodology was used to investigate the performance of motor speed control. For the controller approach, proportional-integral (PI) and proportional-derivative (PD) controllers were investigated. Simulation results using MATLAB (Simulink) software is presented. Furthermore, investigation of the PI, and PD performance shows that the PI controller performed poorly due to existence of high peaks, overshoots and rise time. However, the PD controller yielded satisfactory results. Hence, PD controller revealed a better performance with a 1.01s settling time and a steady state error of 1.0 as against that of the PI controller which was unstable, an overshoot of approximately 96% and a steady state error of 1.22.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"103 46","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141820743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Factors affecting hazard recognition in construction site operations in Nigeria","authors":"I. Ijaola, O. H. Omolayo, Chidozie Charles","doi":"10.4314/njt.v43i2.6","DOIUrl":"https://doi.org/10.4314/njt.v43i2.6","url":null,"abstract":"Identifying hazards is necessary for preventing accidents in construction site operations. In light of this assertion, construction professionals must recognise hazards in site operation. However, recognising hazards remains an issue of concern in the construction industry. Invariably, it is expedient that factors affecting hazard recognition be investigated. The study, therefore, aims to examine the factors affecting hazard recognition in construction site operations and test this hypothesis: ‘there is no significant difference in factors affecting hazard recognition among construction professionals based on their work experience’. Adopting a quantitative research design and cross-sectional research strategy, a questionnaire with 13 factors adapted from literature was used to elicit information from construction professionals. From the median calculated, the factor with the highest value was “multiple hazards associated with a single source of the task”. Furthermore, the study discovered a significant difference in six of the thirteen factors affecting hazard recognition. Because of this, it was concluded that the experience of construction professionals affects their perception of the factors affecting hazard recognition for the six factors. All these issues taken into account, safety experts in construction industry responsible for health and safety training should consider the experiences of construction professionals when developing curriculum on hazard recognition.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"119 50","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141820936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}