Nigerian Journal of Technology最新文献_第3页

Assessing vertical accuracies of satellite-DEM for terrain modelling in Akure, Nigeria 评估用于尼日利亚阿库雷地形建模的卫星-DEM 的垂直精度

Nigerian Journal of Technology Pub Date : 2024-07-19 DOI: 10.4314/njt.v43i2.22

I. U. Nzelibe, I. N. Mogaji, H. Tata

{"title":"Assessing vertical accuracies of satellite-DEM for terrain modelling in Akure, Nigeria","authors":"I. U. Nzelibe, I. N. Mogaji, H. Tata","doi":"10.4314/njt.v43i2.22","DOIUrl":"https://doi.org/10.4314/njt.v43i2.22","url":null,"abstract":"This research conducts a comparative analysis of the vertical accuracies of satellite-derived Digital Elevation Models (DEMs) in the Akure South Local Government Area, Ondo State, Nigeria. The DEMs assessed were obtained from three open-source satellite missions: Sentinel-1A, ALOS PALSAR, and TanDEM-X. The reference Ground Control Points (GCPs) used in the evaluations comprised 133 GCPs of 2nd and 3rd-order accuracy acquired from the Office of the Surveyor General, Ondo State, and through field surveys using the South Galaxy-1 Differential GPS. These obtained GCPs provided extensive coverage of the study area. The evaluation was undertaken based on the land cover, which was established by dividing the study area into open (built-up and bare land) and vegetation-covered (agricultural and forested) areas. The vertical accuracies of the satellite-based DEM collected within the study area were then compared and analyzed. The results revealed that Sentinel-1A and TanDEM-X were the most suitable in both open and vegetation-covered parts of the study area, with Sentinel-1A exhibiting the best performance. The effect of vegetation cover was mostly felt by ALOS PALSAR. Sentinel-1A and TanDEM-X displayed commendable vertical accuracies, deemed highly suitable for applications in topographic mapping, as shown by an RMS of less than 2m. This research recommends the open-source satellite DEMs Sentinel-1A and TanDEM-X for planning and engineering applications because they offer the highest accuracy among their counterparts within Akure and its environs.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"118 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141822285","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}

引用次数: 0

Assessment of the feasibility of Aku small hydropower project using RETscreen Energy Model Software 使用 RETscreen 能源模型软件评估 Aku 小水电项目的可行性

Nigerian Journal of Technology Pub Date : 2024-02-14 DOI: 10.4314/njt.v42i4.8

O. Chinyere, Y. Sanusi, D. Kulla

引用次数: 0

Conceptual design and analysis of a tricycle mounted solar-powered photovoltaic cold room system 三轮车太阳能光伏冷藏室系统的概念设计与分析

Nigerian Journal of Technology Pub Date : 2024-02-14 DOI: 10.4314/njt.v42i4.5

A. Akinsade, J. Eiche, A. Akinola, M.O. Famodun

{"title":"Conceptual design and analysis of a tricycle mounted solar-powered photovoltaic cold room system","authors":"A. Akinsade, J. Eiche, A. Akinola, M.O. Famodun","doi":"10.4314/njt.v42i4.5","DOIUrl":"https://doi.org/10.4314/njt.v42i4.5","url":null,"abstract":"Energy crisis in developing countries is worrisome, and this has made the preservation and transportation of medical and perishable food items a common problem. Most conventional refrigeration systems operate with electricity; however, there are regions where it is difficult or not cost efficient to provide electric service. Therefore, this research seeks to solve the problems of inconsistent, irregular and complete non availability of power supply required to keep food products and drugs refrigerated over a long period of time by designing a tricycle mounted solar-powered cold room. The tricycle mounted solar-powered cold room designed consists of a refrigeration system having a compressor, a condenser, an expansion valve and an evaporator; a solar system having a photovoltaic (PV) module, charge regulator, storage battery and DC to AC inverter; and a tricycle for easy distribution and safe delivery of refrigerated items. A comprehensive analytical design was performed on each of the systems and the design results showed that the solar-powered cold room has refrigerating cooling load, PV array size, battery cap, and inverter power of 986 W, 275 W, 94 kWh, and 8000 W respectively. A structural analysis was also carried out on the tricycle chassis using the finite element method on Autodesk Inventor software. The results showed that the maximum von misses stress experienced by tricycle chassis was 56.96 MPa which is significantly lower than the yield strength of the chassis material used in the design, indicating a robust structural integrity and can therefore be used to carry the loads that it will be subjected to without deformation.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"77 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139779299","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}

引用次数: 0

Conceptual design and analysis of a tricycle mounted solar-powered photovoltaic cold room system 三轮车太阳能光伏冷藏室系统的概念设计与分析

Nigerian Journal of Technology Pub Date : 2024-02-14 DOI: 10.4314/njt.v42i4.5

A. Akinsade, J. Eiche, A. Akinola, M.O. Famodun

{"title":"Conceptual design and analysis of a tricycle mounted solar-powered photovoltaic cold room system","authors":"A. Akinsade, J. Eiche, A. Akinola, M.O. Famodun","doi":"10.4314/njt.v42i4.5","DOIUrl":"https://doi.org/10.4314/njt.v42i4.5","url":null,"abstract":"Energy crisis in developing countries is worrisome, and this has made the preservation and transportation of medical and perishable food items a common problem. Most conventional refrigeration systems operate with electricity; however, there are regions where it is difficult or not cost efficient to provide electric service. Therefore, this research seeks to solve the problems of inconsistent, irregular and complete non availability of power supply required to keep food products and drugs refrigerated over a long period of time by designing a tricycle mounted solar-powered cold room. The tricycle mounted solar-powered cold room designed consists of a refrigeration system having a compressor, a condenser, an expansion valve and an evaporator; a solar system having a photovoltaic (PV) module, charge regulator, storage battery and DC to AC inverter; and a tricycle for easy distribution and safe delivery of refrigerated items. A comprehensive analytical design was performed on each of the systems and the design results showed that the solar-powered cold room has refrigerating cooling load, PV array size, battery cap, and inverter power of 986 W, 275 W, 94 kWh, and 8000 W respectively. A structural analysis was also carried out on the tricycle chassis using the finite element method on Autodesk Inventor software. The results showed that the maximum von misses stress experienced by tricycle chassis was 56.96 MPa which is significantly lower than the yield strength of the chassis material used in the design, indicating a robust structural integrity and can therefore be used to carry the loads that it will be subjected to without deformation.","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"456 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139838979","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}

引用次数: 0

Rice husk and snail shell ash as partial replacement of ordinary Portland cement in concrete – A review 稻壳和蜗牛壳灰在混凝土中部分替代普通硅酸盐水泥 - 综述

Nigerian Journal of Technology Pub Date : 2024-02-14 DOI: 10.4314/njt.v42i4.2

A. Alhassan, A. Aboshio, O.A. Uche

引用次数: 0

Evaluation of rainfall rates and rain-induced signal attenuation for satellite communication in the South-South Region of Nigeria 尼日利亚南部地区卫星通信降雨率和雨水引起的信号衰减评估

Nigerian Journal of Technology Pub Date : 2024-02-14 DOI: 10.4314/njt.v42i4.7

U. Ukommi, K. Ekanem, E. Ubom, K. Udofia

{"title":"Evaluation of rainfall rates and rain-induced signal attenuation for satellite communication in the South-South Region of Nigeria","authors":"U. Ukommi, K. Ekanem, E. Ubom, K. Udofia","doi":"10.4314/njt.v42i4.7","DOIUrl":"https://doi.org/10.4314/njt.v42i4.7","url":null,"abstract":"Rain fade causes signal attenuation which can relatively results in signal quality performance degradation, increased pathloss and coverage area reduction in satellite communication networks, most especially in the tropics and at higher operational frequencies above 10GHz. Analysis of rain attenuation provides useful insight for satellite communication engineers for efficient network planning and design within the region of study. Hence this paper presents threeyear analysis of signal-induced attenuation in the South-South States of Nigeria for the cities of Port-Harcourt, Uyo, Calabar and Eket, whose terrain characteristics could be generalized to represent urban, sub-urban and rural terrains in Nigeria. The International Telecommunications Union Radio-wave propagation (ITU-R P618-13) model was used to estimate the long-term rain attenuation at 10GHz, 20GHz and 30GHz for satellite communication applications. Results obtained at 10GHz, 20GHz and 30GHz operational frequencies show that at high frequency, rain fade can cause signal attenuation levels in the south-south region of Nigeria. In all, Calabar recorded the highest rain rate and corresponding highest attenuation level of 96.13dB at 30GHz compared to 50.29dB at 20GHz for the period under review. ","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"47 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139779149","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}

引用次数: 0

Assessment of the feasibility of Aku small hydropower project using RETscreen Energy Model Software 使用 RETscreen 能源模型软件评估 Aku 小水电项目的可行性

Nigerian Journal of Technology Pub Date : 2024-02-14 DOI: 10.4314/njt.v42i4.8

O. Chinyere, Y. Sanusi, D. Kulla

引用次数: 0

Evaluation of rainfall rates and rain-induced signal attenuation for satellite communication in the South-South Region of Nigeria 尼日利亚南部地区卫星通信降雨率和雨水引起的信号衰减评估

Nigerian Journal of Technology Pub Date : 2024-02-14 DOI: 10.4314/njt.v42i4.7

U. Ukommi, K. Ekanem, E. Ubom, K. Udofia

{"title":"Evaluation of rainfall rates and rain-induced signal attenuation for satellite communication in the South-South Region of Nigeria","authors":"U. Ukommi, K. Ekanem, E. Ubom, K. Udofia","doi":"10.4314/njt.v42i4.7","DOIUrl":"https://doi.org/10.4314/njt.v42i4.7","url":null,"abstract":"Rain fade causes signal attenuation which can relatively results in signal quality performance degradation, increased pathloss and coverage area reduction in satellite communication networks, most especially in the tropics and at higher operational frequencies above 10GHz. Analysis of rain attenuation provides useful insight for satellite communication engineers for efficient network planning and design within the region of study. Hence this paper presents threeyear analysis of signal-induced attenuation in the South-South States of Nigeria for the cities of Port-Harcourt, Uyo, Calabar and Eket, whose terrain characteristics could be generalized to represent urban, sub-urban and rural terrains in Nigeria. The International Telecommunications Union Radio-wave propagation (ITU-R P618-13) model was used to estimate the long-term rain attenuation at 10GHz, 20GHz and 30GHz for satellite communication applications. Results obtained at 10GHz, 20GHz and 30GHz operational frequencies show that at high frequency, rain fade can cause signal attenuation levels in the south-south region of Nigeria. In all, Calabar recorded the highest rain rate and corresponding highest attenuation level of 96.13dB at 30GHz compared to 50.29dB at 20GHz for the period under review. ","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"589 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139839024","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}

引用次数: 0

Development of passenger’s waiting time model at Bus Public Transit Terminal 开发公交总站乘客候车时间模型

Nigerian Journal of Technology Pub Date : 2024-02-14 DOI: 10.4314/njt.v42i4.3

M.N. Ibrahim, J.K. Ede

{"title":"Development of passenger’s waiting time model at Bus Public Transit Terminal","authors":"M.N. Ibrahim, J.K. Ede","doi":"10.4314/njt.v42i4.3","DOIUrl":"https://doi.org/10.4314/njt.v42i4.3","url":null,"abstract":"Passenger’s waiting time at terminal is a key constituent of travel time, as long waiting time increases the overall journey time. In Nigeria, urban-rural bus transit system is associated with long waiting time. This study evaluates bus transit users’ waiting times at terminal with perceived and actual waiting times (PWT and AWT) along with associated bus service frequency (BSF). Bus public transit operating from Enugu city (as origin) to 6 local government areas (Awgu, Isi-Uzo, Nkanu west, Nsukka, Oji River and Udenu) of the state as destinations was studied. Data were collected on AWT and PWT at Old Park, Enugu for 30 days from 8 am to 6 pm (5 days per route). Data on AWT and PWT were collected based on passenger’s observation and oral interview, respectively. The study discovered that transit users incurred long waiting times, with 80 – 90% of the users incurring AWT of 21 minutes to 1 hour and more, indicating a poor service quality. Also, 80 – 90% of the users overestimated their PWT by 25 – 60%. At 95% confidence level, PWT is significantly longer than AWT (P < 0.05) for all the routes. A passenger’s perceived waiting time model was developed for predicting PWT based on AWT. The model developed showed that PWT is strongly correlated with AWT, with an R2 = 0.9591 and F-significance < 0.05. This suggests that that AWT accounts for 96% variability in PWT. Consequently, the model developed exhibits a reasonable accuracy, hence, can be applied for prediction of passenger’s perceived waiting time. The mean BSF for Enugu – Nsukka and Enugu – Oji River routes were 30 and 21 buses per day, respectively. While, the other 4 routes recorded lower values of 7 – 9 buses per day, resulting in longer waiting times than the other 2 routes. The implication of long passengers’ waiting time suggests the need for shifting from unscheduled to scheduled operation and improved BSF by shortening bus headways to minimize waiting time. ","PeriodicalId":33360,"journal":{"name":"Nigerian Journal of Technology","volume":"53 51","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139777916","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}

引用次数: 0

Rice husk and snail shell ash as partial replacement of ordinary Portland cement in concrete – A review 稻壳和蜗牛壳灰在混凝土中部分替代普通硅酸盐水泥 - 综述

Nigerian Journal of Technology Pub Date : 2024-02-14 DOI: 10.4314/njt.v42i4.2

A. Alhassan, A. Aboshio, O.A. Uche

引用次数: 0