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Response characteristics of a negative temperature coefficient thermistor
Get PDFThis article focuses on the thermistor as a device that is widely used for temperature measurement and control in most electrical and electronic devices and appliances. The research is based on the type of thermistor used in photocopiers with particular reference to Minolta Bizhub (model-210) photocopier. The resistance and temperature were recorded by the application of conventional heat to deduce the response curves of resistance versus temperature and resistance/time. Results obtained from the characteristics show that the thermistor employed in the photocopier is a negative temperature coefficient (NTC) device. Also, there was a time variation in the response of the thermistor resistance to temperature changes, which indicates that the thermistor under test functions as a temperature control device. The shape of resistance versus temperature curve appeared to be similar to that of a typical NTC thermistor characteristics
Analysis of energy revenue and electrical power losses in distribution line
Get PDFThis study presents the analysis of energy revenue and electrical power losses in distribution network, aimed to determine the energy losses on power distribution system. The 11kV power transmission line at Ujokuen community feeding to Benson Idahosa University was investigated. The following data were obtained as follow: energy delivered, energy billing, total cash amount, billed collected and correspond percentage. From the research work various technical power losses associated with power distribution network were determined and their effect on energy delivered and energy billing and corresponding difference under the area of investigation. It was observed that energy delivered is not constant or linear for the year 2013. The comparison of energy delivered and energy billed for various years were determined. It was observed that there is decreased in energy delivered and energy billed from 2013 to 2015 and the system witnessed a slightly increase of energy delivered and energy billed from 2016 to 2018. The energy level differentials are due to copper losses, energy theft and core loss
Heavy metals pollution potentials in the National Iron Ore Mining Company, Itakpe
Get PDFHeavy metals pollution potential in National Iron Ore Mining Company, Itakpe was investigated. Two mining sites located at the east mining pits such as M3O, which is 370 m above sea level and M2O, which is 350 m above sea level were studied. Sequential extraction techniques was utilised to examine the distribution effect of the heavy metals pollution potential on the environment. Twelve representative (six-soil, two-sediment, two-plant and two-water) samples were collected, pre-treated and prepared for this study. The atomic absorption spectrometer was used to analyse the concentration of the metals after the sequential and single-stage extractions were determined. Results showed that Chromium, Arsenic, Cadmium and Copper are more bioavailable in the study area than Lead and Iron. This findings indicate that human, animals and plants are exposed to toxic elements (metals and metalloids)
Evaluation of net radiation using the autoregressive models with higher orders over Nigeria
Get PDFIn this study, monthly surface net radiation data were collected from the Nigeria Meteorological Agency, Lagos covering a duration of 31 years (1983- 2013) spatially distributed across the four climatic regions: Semi-Arid (SAR), Sub-humid Dry (SHD), Sub-humid Humid (SHH) and Humid (HUM) regions. The net radiation was evaluated using different forms of Auto-Regressive models – AR {p} where p is the number of orders of the auto-regressive. The analysis showed that AR {4} performed best in all the regions and stations investigated. Regionally, AR {4} has maximum values of coefficient of determination of 0.8127 in HUM, 0.7876 in SHH, 0.5765 in SHD and 0.7973 in SAR regions. It can be concluded that the higher the order of auto-regressive models, the more accurate estimation of net radiation it will give irrespective of location in Nigeria
Comparative study and experimental analysis of pellets from biomass sawdust and rice husk
Get PDFSawdust and rice husk are available in abundance and indigenous in Nigeria but have not been exploited because they cannot be used directly in combustion processes due to their loose form unless by pelleting or briquetting. This experimental study assesses the potential of pellets from sawdust (SD) and rice husk (RH). Pallet samples collected from mills were thereafter optimized in ratios (i.e. 90%RH:10%SD, 80%RH:20%SD, 70RH:30SD, 60%RH:40%SD, 50%RH:50%SD, 100%RH and 100%SD) using mixing ratio optimization model. Seven samples were produced using a manual screw press machine and were subsequently categorized in terms of calorific value (CV), proximate and ultimate analyses using the ASTM standards. Results showed that the 100%RH pellets have higher CV of 31,026.3kJ/kg and the 100%SD a value of 26,088.3kJ/kg while the optimized pellets range from 25,867.39kJ/kg to 27,063.60kJ/kg. The CV decreases with increasing ash content of the pellets. It was also observed from the proximate analysis that the 100%RH has low percentages of moisture content, volatile matter and ash content compared to others. The optimized pellets showed that SD has the tendency to reduce the sulfur content in RH; hence, a promising alternative source of energy to the conventional fossil fuel
Analysis of radio frequency spectrum usage using cognitive radio
Get PDFThis paper presents the analysis of radio frequency (RF) spectrum usage using cognitive radio. The aim was to determine the unused spectrum frequency bands for efficiently utilization. A program was written to reuse a range of vacant frequency with different model element working together to produce a spectrum sensing in MATLAB/Simulink environment. The developed Simulink model was interfaced with a register transfer level - software defined radio, which measures the estimated noise power of the received signal over a given time and bandwidth. The threshold estimation performed generates a 1\0 output for decision and prediction. It was observed that some spectrum, identified as vacant frequency, were underutilized in FM station in Benin City. The result showed that when cognitive radio displays “1” output, which is decision H1, the channel is occupied and cannot be used by the cognitive radio for communication. Conversely, when “0” output (decision H0) is displayed, the channel is unoccupied. There is a gradual decrease in the probability of detection (Pd), when the probability of false alarm (Pfa) is increased from 1% to 5%. In the presence of higher Pfa, the Pd of the receiver maintains a high stability. Hence, the analysis finds the spectrum hole and identifies how it can be reuse
Effects of energy band structure on gallium arsenide based MOSFET
Get PDFThis research work is focused on material science and semiconductor engineering. It emphasized on the semiconductor material such as Gallium arsenide (GaAs). The Gallium arsenide semiconductor material was used as a group III-V compound for metal-oxide semiconductor field effect transistor (MOSFET) modeling. The band-gap energy structures were analyzed by using material parameters such as Varshni parameters, temperature and doping concentrations. Then, an electrical characteristic was carried out depending on the current and voltage relationship. The current flowing in the device is associated with a gate voltage applied to the device. From this paper, the analysis of MOSFET modeling was investigated using mathematical equations and MATLAB simulation
Design and implementation of a prototype active infrared sensor controlled automatic sliding door for mitigation of coronavirus disease 2019 (COVID-19)
Get PDFThe door is an essential part of any structure that provides access and security of lives and properties. The manual operation of a door could be cumbersome and laborious when the traffic volume is high. Also, it has been observed that doors could serve as a medium of spreading the deadly coronavirus disease 2019 (COVID-19) infection. Therefore, a prototype automatic sliding door that plays a crucial role in curbing the spread of this infectious diseases has been designed and implemented in this paper. The design of the prototype sliding door is in two parts namely; the structural part and the automation part. The structural design of the door was achieved using the Microsoft Visio 2016 while the design of the automation system was achieved using express printed circuit board. The implementation of the structural part was achieved using 1 inch particle board while the implementation of the automation system was based on the components like the active infrared sensor, resistors (10 kΩ), capacitor (1000 µF), transistors (TIP41 Q8, BC548 Q7), LED indicators, press button switch, pulley system, drive belt, stepper motor (IP65), and ATMEGA 8 microcontroller. The result of the tests carried out on the door showed that the prototype automatic sliding door was characterized by average opening time, closing time, delay time, and optimal sensing range of 3.10 s, 3.05 s, 5.72 s, and 23.5 cm, respectively. It can therefore be concluded from this work that the prototype automatic sliding door is effective in overriding the manual operation of the door
Determinants of an Effective Solid Wastes Collection at the Workplace: the Experience of the Council for Scientific and Industrial Research-Institute of Industrial Research, Accra, Ghana
Get PDFThe inefficient collection of solid wastes is a global phenomenon that has received attention in recent years for the ever-increasing annual waste generation records. However, indicators to the effective application of the amassing routs are missing. Hence, the generally accepted source-sorting model was explored to identify the determinants that will enhance source separation of wastes at the workplace. This paper presents a foremost report on the indicators to an effective operation of solid wastes source segregation. A quantitatively examined data was collected in sixty-six working days during a monitoring and evaluation process of twenty sets of twin-dustbins that were located at the study area. The generated solid wastes were commonly sorted (65%) in comparison with the mixed collection. Most of the wastes were separated on the third month (80%) of education compared to the first (54%) and second months (61%). Wednesday displayed the working day with the utmost sorted wastes (73%) compared to the other days. All dustbins recorded impressive sorting at the different locations in the Institute. A little over one thousand Ghana cedis savings was made in the first year. Tested null hypothesis showed that, duration and timing of continuous education were significant determinants of the efficient source segregation, relative to the dustbin locations. Therefore, the daily education of waste generators on how to separate wastes at source and the economic benefits will enhance source separation irrespective of the location
Economic Analysis of Cassava Production: Prospects and Challenges in Irepodun Local Government Area, Kwara State, Nigeria
Get PDFThis study was carried out to analyse cassava production, prospects and challenges in Irepodun local government area, Kwara State, Nigeria. It aimed to examine the determinant variables and determine the profitability level of cassava enterprises. The study was based on primary data obtained with the aid of structured questionnaire from 100 cassava farmers drawn through multi-stage sampling techniques from the study area. Data were analysed using descriptive statistics, ordinary least square (OLS) regression model and gross margin analysis. The result of the OLS regression estimates showed that farm size, cost of fertilizer application, farm size, herbicides, family and hired labour were significant variable affecting cassava production in the study area. Fertilizer, farm size and hired labour are significant at 1% while herbicide and family labour are significant at 10%. The study found that the average gross margin per hectare for cassava production in the study area was ₦24,749.28 ($65.30) with a gross benefit ratio of 1.38. This shows that for every ₦1 invested in the business of cassava production, there is a corresponding profit of ₦1.38. The major challenges identified in cassava enterprise are huge transportation cost, high cost of production, lack of improved cassava cultivars, and lack of market linkages. The study concluded despite the problem encountered in the study area, cassava production is profitable and can serve as a panacea for economic improvement of households. Therefore, the study recommends that basic inputs such as improved cassava varieties, herbicides and fertilizer should be made available at affordable price. Also, infrastructural facilities such as good road network and improve marketing channels should be provided in order to sustain current cassava production rate and economic gains from the production