1 |
Author(s):
Abdullahi, Hamza Sulayman.
Page No : 1-9
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Effect of seed points on the geometric and mechanical properties of Voronoi foams
Abstract
Foams are cellular materials with unique mechanical properties. The geometric properties of these structures have been proved to be responsible for their unique mechanical properties. In the process of modeling and simulation, reproducing those geometric properties accurately is still a challenge to researchers. This paper provides details on the geometric modeling techniques used to model the foams and investigates the effects of the initial seed points on the geometric and mechanical properties. Unit cell repetition methods such as Kelvin cell, Gibson-Ashby cell as well as randomly generated models such as Poisson Voronoi, Hardcore Voronoi, and Laguerre Voronoi were all investigated and their effectiveness in reproducing the geometric properties of the foams and predicting the elastic properties is demonstrated.
2 |
Author(s):
Tasiu Ashiru Sulaiman, Abdulhamid Aliyu Ozovehe, Ibrahim Aliyu.
Page No : 10-18
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SUITABILITY OF USING BUSH PEBBLE (COARSE AGGREGATE) IN THE PRODUCTION OF CONCRETE
Abstract
This study is aimed at evaluating the suitability of using Bush pebble (coarse aggregate) sourced from the Kangiwa village in Kebbi Niger State, Nigeria in the production of concrete with 1:2:4 and 0.45, 0.55 and 0.65 as a mix ratio and water cement ratios respectively. The coarse aggregate (Bush pebble) used has a nominal size of 20 mm with a specific gravity of 2.65 and a bulk density of 1345.1 kg/m3. The results of workability (slump) and compaction factor show that as the water-cement ratio increases the workability (slump) and compaction factor increase. Additionally, the densities of concrete produced with different water-cement ratios fall within the limits of 2200 kg/m3 to 2600 kg/m3. On the other hand, the compressive strength of concrete produced with Bush pebble increases as the curing age and water-cement ratio increase. The regression model developed for the compressive strength of concrete is adequate for predicting the compressive strength of concrete produced with Bush pebble (aggregate). It was concluded that, based on different tests carried out, the Bush pebble (aggregate) can be used in the production of concrete as a substitute for normal coarse aggregate.
3 |
Author(s):
Nasiru Bello Kadandani.
Page No : 19-27
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EXPERIMENTAL IMPLEMENTATION OF SORTING ALGORITHM BASED VOLTAGE BALANCING OF MODULAR MULTILEVEL CONVERTER
Abstract
Of paramount important to the proper operation of modular multilevel converter (MMC) is the submodule (SM) capacitor voltage balancing. Two major approaches proposed to achieve this task are distributed method and centralized method. This paper presents an experimental implementation of the centralized SM capacitor voltage balancing control strategy in MMC based on sorting algorithm. The concept was experimentally demonstrated on a laboratory prototype MMC with four SMs per arm. The results show that the SM capacitor voltages are properly balanced and regulated to their reference values. Further, the resultant output voltage and current waveforms exhibit perfect harmonic performance with fundamental switching frequency; thus confirming the effectiveness of the control method.
4 |
Author(s):
Nasiru Bello Kadandani, Isiyaku Abubakar.
Page No : 28-39
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ON EXPLORING THE POWER QUALITY ENHANCEMENT CAPABILITY AND OTHER ANCILLARY FUNCTIONALITIES OF SOLID STATE TRANSFORMER IN THE DISTRIBUTION GRIDS
Abstract
Nowadays, the distribution grids are facing technical challenges due to the increased connection of sizeable loads like electric vehicle (EV) charging stations as well as large penetration of distributed renewable energy resources (DRERs) notably wind energy conversion system (WECS) and solar power plant (SPP), thus resulting in some operational issues in the form of power quality disturbance, reliability issues and grid congestion. To this extent, solid state transformer (SST) has been envisioned as a promising device for improving the power quality, providing a bidirectional power flow capability as well as ensuring a smooth and safe way of interfacing DRERs with the distribution grid. This paper reviews the basic power quality parameters in electrical power system, the role of SST in power quality improvement as well as some other ancillary services that SST can offer to the grid which cannot be achieved with the conventional line frequency transformer (LFT).
5 |
Author(s):
Muhammad Buhari, Jorge Angarita Marquez, Geev Mokyryani.
Page No : 40-48
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OPTIMIZATION OF DISTRIBUTION SYSTEMS INCORPORATING DISTRIBUTED GENERATION AND BATTERY ENERGY STORAGE SYSTEMS
Abstract
This paper proposes a novel a multi-stage stochastic problem to minimize the cost of the Distribution System (DS) including the Distribution Network (DN) and customer costs. This paper proposes a central planning approach where the decision variables are the sizing, siting, and operation of Battery Energy Storage Systems (BESS), the sizing and siting of Distributed Generation (DG) and capacity of the distribution lines. The algorithm estimates the optimal BESS’s energy storage capacity as well as the maximum hourly delivery capacity. The customers’ objective function is the capacity and energy payments minus the saving and revenue from DG. The Distribution Network Operator’s (DNO) goal is to minimize the cost of the distribution network and BESS’s investments and operational costs. Since the model has a long-term approach, the paper presents the implementation of Expected Value as decision criterion to handle the uncertainty. The impact of the remuneration rules for DG on customers’ and DN’s cost are calculated. The results show that the incorporation of DG brings important benefits to the customers while BESS provide modest improvements.
6 |
Author(s):
Baba Saleh Abba, Nura J. Shanono.
Page No : 49-60
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Assessment of Deficit Irrigation and Mulch on Onion Growth and Yield Parameters in Semi-arid Region Nigeria
Abstract
Water insufficiency is one of the major challenges for irrigated agriculture particularly in water-stressed regions which prompted the need to promote water-saving irrigation methods such as deficit irrigation (DI) and mulch practices (MP). An experiment was conducted to assess the effect of DI and MP on the productivity of Onion at Dala Alamderi Irrigation Site, Borno State, Nigeria, during 2020/2021 irrigation season. The experiment consisted of 4 levels of irrigation (100, 85, 70, and 55% of weekly reference evapotranspiration and 4 levels of mulches (no mulch NM, synthetic plastic SM, wood shaving WM and rice straw RM). The treatments were replicated 3 times making 48 plots and laid using a split-plot design. The data on Onion height, canopy cover, number of leaves, bulb yield and water use efficiency (WUE) were collected and analyzed using the Statistics 8.0 software package. The interaction effect of DI and MP has significantly (p<0.05) affect the Onion growth parameters, yield and WUE. The higher growth parameters were recorded at mulched compared to no-mulch plots. However, among the mulched, plots irrigated at 85% with SM mulch yielded high values of Onion height, canopy cover and number of leaves of 42cm, 72% and 8 respectively, Whereas the lower mean values of the Onion growth parameters were recorded at plots irrigated at 70 and 55% under WM and RM mulch. Higher Onion yields of 15.10 t/ha was recorded at plots irrigated at 85% with SM mulch, which was 19.4% higher than plots irrigated at 100% with no mulch treatment. The highest crop water use efficiency value of 19.08 kg/m3 was observed at 85% irrigation with SM mulch. Meanwhile, the lowest crop WUE of 12.53 kg/m3 were obtained for treatment at 100% irrigation under no-mulch. The crop WUE increases as the irrigation decreases under the mulching order of NM, RM, WM and SM mulch during the cropping season. It can be concluded that the Onion farmers in the study area should adopt the DI at 85% with SM mulch that increased Onion bulb yield production by 19.4% and saved water by 15% when compared to the conventional full irrigation with no mulch. The saved water could be used to expand more land for crop cultivation.
7 |
Author(s):
Lawal Muhammad Bello, Abdullahi Musa Auyo, Suleiman Aliyu Babale.
Page No : 61-70
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BOOSTING THE SUM RATE INA THREE USER NOMA NETWORK USING INSPIRED CR-NOMA POWER ALLOCATION
Abstract
Fifth generation (5G) network which utilizes non-orthogonal multiple access (NOMA) to achieve some of its data requirement and maintain its advantages of low latency, high throughput and spectral efficiency which needs to be maximized to accommodate more users and enhance network capacity. This research proposes Rayleigh fading approach and inspired cognitive radio (CR-NOMA) power allocation to boost the sum rate in a three-user single carrier (SC-NOMA) system. The adopted model allocates power based on users’ channels condition while guaranteeing the minimum power required by the weakest user. This leads to simulations that involve three users with different channel conditions where their total sum rate is calculated and compared with the sum rate achieved when conventional fixed (F-NOMA) power allocation is used. The results revealed that simulation with three users arranged in two different forms between two user NOMA system coupled with lone unpaired user communicated using orthogonal multiple access (OMA) and three user SC-NOMA where both uses F-NOMA power allocation yields the maximum sum rate of 1.8 x 10-4bps/Hz and 0.3 x 10¬¬¬-4bps/Hz respectively. While inspired CR-NOMA power allocation yields a maximum sum rate of 16 bps/Hz for SC-NOMA and 7.5 bps/Hz for typical NOMA-OMA arrangement. The result shows a significant improvement over the existing system. Furthermore, it was observed that high sum rate in SC-NOMA is due to users’ distinct channel conditions while that of typical NOMA-OMA is due to large sum rate achieved by the lone unpaired user utilizing single spectrum. This makes room for more users to be accommodated without fear of signal degradation.
8 |
Author(s):
Oputa, O., Obi, P. I., Diyoke, G. C., Onwuka, I. K., Ezeonye, C. S..
Page No : 71-83
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EFFECTS OF VARYING FAULT IMPEDANCE ON DISTANCE PROTECTION SCHEMES OF 11 KV DISTRIBUTION SYSTEMS
Abstract
Distance protection schemes are used in the protection of transmission and distribution lines and they use distance relay in their operations. The protection scheme is always partitioned into two or more zones and each zone is a certain percentage of the entire length of the line (which may also include the next line). With all things being equal, the tripping of the relays is solely a function of the zones where the fault occurred, that is the location of the occurrence of the fault. However, it has been shown in this paper through simulations in Power System Computer-Aided Design (PSCAD) that the fault impedance value also slightly affects the trip location. For a double line (LL) fault (between AB) occurring in Zone 1 in our test 11 kV distribution line, the simulation in PSCAD shows that the distance relay/protection system trips inaccurately in Zone 2 for a fault impedance of 0.1Ω and 0.5Ω and trips accurately in Zone 1 for fault impedance of 1Ω, 5Ω, and 10Ω. This indicates that tripping zone in distance protection schemes are not solely dependent on fault locations but also slightly dependent on the fault impedance.
9 |
Author(s):
Ezeonye, C. S., Onwuka, I. K., Obi, P. I., Oputa, O..
Page No : 84-94
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A STUDY OF MOTOR SENSITIVITY TO PARAMETERS VARIATION IN EXTERIOR PERMANENT MAGNET SYNCHRONOUS MOTOR
Abstract
This paper presents the study of motor sensitivity to parameters variation on the dynamic behaviour of exterior permanent magnet synchronous motor with the aid of matlab m-file for simulation. The motor differential models are indicated in reference frame of the rotor with rotor angular position, mechanical rotor speed, q- and d-axes stator currents as state variables. The motor parameters used in this research is a 3-phase, 2 KW, 50 Hz, 4 poles, 220 V. The results showed that increase in frequency leads to increase in motor synchronous speed (1500 rpm to 2250 rpm to 3000 rpm for 50 Hz, 75 Hz and 100 Hz respectively) due to its direct relation, and slightly increased electromagnetic torque and output power. The effect of increase in resistance of the stator winding shows that it reduces the magnitude of ripple of the output characteristics (torque, power and speed) but maintains the same steady state value, while the effect of increase in coefficient of viscous friction decreases the magnitude of ripple and increase the value of the steady state. Similarly, variation on the inertia moment of the motor has little or no effect on the motor output characteristics. Effect of load variation only affects the output power and air-gap torque of the motor as increase or decrease in load leads to increase or decrease in output power and air-gap torque respectively. The loading of the motor is not to exceed the 15 Nm otherwise, the motor will operate in reverse condition. The results gotten in this research as compared to other literatures gives a clear understanding and knowledge of the parameters required of a particular motor for improve operating performance with respect to the design requirement.
10 |
Author(s):
SF Kolawole, M. Hamza.
Page No : 95-103
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ENHANCEMENT OF RECEIVED POWER DISTRIBUTION OF A NON-DIRECTED LoS INDOOR VISIBLE LIGHT COMMUNICATION SYSTEM
Abstract
Visible light communication system for an indoor environment is presented both in terms of line of sight and non light of sight scenarios. Both scenarios have been simulated jointly to produce a received power distribution across a communication environment. The simulations were carried out considering two separate 9-transmitters configurations of which one is a conventional arrangement and the other is a novel arrangement presented in this work. The results were compared and analysed and the novel transmitter configuration was found to have better received power distribution by 9% without diminishing maximum received power where there is high probability of having a receiver.
11 |
Author(s):
Mohammed Tajudeen Jimoh.
Page No : 104-112
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Mathematical modelling of single slope solar still with ambient temperature and global irradiance
Abstract
This work models a single slope solar still. The ordinary differential equation describing the operations of the still are presented. In addition, the models for the two major inputs of the still, the ambient temperature and the global irradiance, are presented. The mathematical models provide for the study of the effects of many variables on the performance indicators of solar - the distillate yield, the water temperature. The variables include depth of water in the still basin, seasons of the year, slope of glass cover, and many variables of construction such as type of glass cover, insulation type and thickness.
12 |
Author(s):
Abubakar, Z.M, Yahaya, B, Ibrahim, Y, Momoh, M. O, Shobowale, K.
Page No : 113-123
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IOT-BASED HEALTH MONITORING SYSTEMS: A REVIEW
Abstract
The emerging technological trend in the healthcare sector is geared towards changing the usual healthcare services and routine medical check-ups from hospital centric to home centric. This offers a reduction in the total expenses spent and reduces the workload on the clinical personnel. As such, remote health monitoring systems based on Internet of Things (IoT) are developed to aid in monitoring some physiological parameters (such as: heart rate, body temperature, blood pressure, glucose level, etc.) of patients at home. The devices often use internet connectivity to effectively monitor the health condition of patients. They are mostly developed using Arduino microcontrollers and sensors. The devices often use IoT platforms such as ThingSpeak for gathering, visualizing, and analyzing the sensed data. In this paper, the significance of developing remote health monitoring systems is discussed. Several literatures using diverse measuring parameters and different approaches were reviewed. The factors necessitating the need for such systems, the objectives for designing the systems, potential for product commercialization, application area in the health sector, and system requirements are discussed.
13 |
Author(s):
Mubarak Danladi Muhammad, Mohammed Abdullahi Gele.
Page No : 124-132
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ANNUAL PERFORMANCE EVALUATION OF SPIRAL TYPE SOLAR WATER HEATER USING LINEAR REGRESSION MODEL
Abstract
A solar water heating system using spiral type flat plate collector was designed, constructed at the old site clinic of Bayero University, Kano. The system comprises of a collector and a storage tank, the collector has an area of 1.62m2. The spiral collector system was tested for 80 days(11 weeks) and performance data were recorded. This data was analysed to find the relationship between performance of the system and the solar radiation intercepted. An empirical model was then developed using the performance data collected for the spiral type solar water heating system. This empirical model can be used to predict the annual performance of the solar water heating system using weather data obtained from metrological centres. The model was found to accurately predict the system performance with a maximum weekly error of 11% and a total error based on the 11 weeks of data collected of 1.55 kWh/m2 corresponding to an error of 2.2%. It was also found out that the energy collected for a spiral type solar collector varies linearly with the solar radiation intercepted and the efficiency is independent on the solar radiation intercepted.
14 |
Author(s):
Umar Muhammad Ahmad, Isa Aliyu Yola.
Page No : 133-139
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Energy Production Potential of Suleja Municipal Solid Waste
Abstract
Suleja Local Government of Niger State Nigeria is located between 9° 12’’N and 7°10” E. Suleja is faced with the twin problem of inadequate electricity and waste management. Although Niger State has not been mentioned prominently as a state with acute waste management problem, there is however a growing evidence that the little that is being generated is not been properly managed. The second of the two principal options for managing MSW in most parts of the world is WtE where the waste is used as a feedstock to produce energy by either thermo-chemical or biochemical means. The MSW of Niger State was characterized using ASTM D5231-92 and sorted into combustibles and non combustibles, the calorific value was determined using Parr 6310 bomb calorimeter and the energy potential was determined using SZR garbage incinerator with thermal efficiency of 81% at 2.5 bar and 〖400〗^o C. The daily disposal of Suleja MSW was found to be about 80000 kg out of which 71787 kg are combustibles. The average calorific value was found to be 21.8 MJ/kg The average energy output in form of steam is between 11.2 - 17.2 MW with an average of 14.7MW of heat.