Root Locus-Based Magnetic Levitation System Stabilization: An Undergraduate Control System Design Approach

The subject of control system design has evolved considerably over the years. Although several design techniques and strategies have been adopted to realize control systems that meet a predetermined set of performance criteria, the fundamental problem remains that of developing controllers to adjust the performance characteristics of a dynamic system in order to obtain a desired output behavior. The dynamic behavior of a magnetic levitation system (MLS) of a ferromagnetic ball is compensated in this paper. Consolidating the exposure of undergraduate students to the rudiments of control system design, the paper employs the classical root locus technique to stabilize the system. A combination of analytical and software-based methods is used to design proportional-derivative and phase-lead compensators based on the linearized model of the system. Complete details of the design approach, from modeling and analysis of the plant to computing the values of the controller parameters, are shown. MATLAB scripts for plotting root loci and simulating the system are provided

Glass-Ceiling and Female Career Advancement: A Study of the Nigeria Police

Despite the remarkable increase in the existence of women in the workforce, the entry of women into higher managerial positions remains restricted. Various studies have confirmed this fact. This phenomenon of hampering women’s upward advancement to senior management positions has been referred to as the glass ceiling effect. This empirical survey shows results of the effect of glass ceiling on female career advancement in the Nigeria Police Force (NPF). The statistical analysis was based on 198 respondents in the NPF indicating cultural role expected of the female gender makes a significant predictor of the female career advancement. Also, career plan and higher education make significant contributions to the studied dependent construct. The effect of counterproductive male behaviour contributed positively but did not make significant statistical contribution to the prediction of the survey dependent construct. However, it is therefore recommended that organizations (both private & public) embark on enlightenment campaign and also incorporate equal opportunity employment policy in their company or organizational policie

A Study of Awareness and Electricity Use Behaviour of On-campus Residence Students in Nigeria

The study explored the awareness and reported energy use behaviour among higher education students in Southwestern Nigeria; examined the relationship between the level of awareness of the impact of energy use behaviour of students and also provides strategies that could be used to improve the level of awareness of stakeholders. We adopted a quantitative survey and questionnaire as instruments for gathering relevant data from end users in the study area and relevant data were analysed using descriptive statistics. The findings revealed that end users had low level of awareness of the negative impact of energy use behaviour 201(81.4%) and had not been trained on energy saving measures. However, they were more aware of the positive impact of energy use behaviour 194(79.0%). The analysis also showed a significant relationship between awareness and reported energy use behaviour; awareness level and turning off light when not needed (r = 0.897, p = 0.001), awareness level and shutting down all computers unless in use (r = 0.189, p = 0.044) and awareness level and leaving computer running overnight (r = 0.452, p = 0.003). The study concluded that the level of awareness of energy saving measures of electricity end users was very low and consequently a lot of energy could be wasted in return. To maximize energy saving potentials of the students, there is need for authorities in tertiary institutions to make effort to raise the awareness of everyone involved; including the management of institutions through an energy efficiency awareness programme, as this could help higher education institutions to achieve energy sustainability and reduce waste. The study developed a framework for improving and enhancing students’ awareness on the impact of energy use behaviour

Heat Energy From Value-Added Sawdust Briquettes Of Albizia Zygia

Sawdust accumulation and disposal at the various sawmills have always created an environmental problem. From some sawmills along Eleweran, Abeokuta the sawdust of a major hardwood species, Albizia zygia wassingled out and collected during conversion at the head rig. The sawdust collected in 30 livestock feed sacs were later transported to Celina Industries where they were densified into briquettes at a pressure of 2000MPa at 4500C and heat intensity of 300% for the production of heat energy and a comparative analysis of the physical properties between the sawdust briquettes and the solid wood of the same species were carried out. The results obtained showed that the briquettes produced using 100% sawdust of Albizia zygia had a lower moisture content of 7.10% than the solid wood (23.76%) of the same species. Also, the heat value and the percentage dry matter of the briquettes were 4.723Kcal-1 and 92.90% respectively which were much higher than the values obtained for the heat value (4.014Kcal-1) and percentage dry matter (76.24%) of the solid wood of the same species. It was concluded that stable briquettes with higher calorific value can be produced from the sawdust of Albizia zygia.Keywords: Briquette, head rig, sawdust, sawmill

Diversity, distribution and abundance of fish species in Lake Asejire, Oyo State, Nigeria

Aquatic systems in Nigeria have suffered stress induced by human activities which alter the natural composition of the water resources. This study investigated the diversity, distribution and abundance of fish species in Lake Asejire. The lake was partitioned based on accessibility into upper, middle and lower sections for the study. Fish species were sampled using monofilament gill nets with stretched mesh sizes ranging from 44.45-169.33mm. Water and fish species were sampled fortnightly for a period of twelve months. Water quality parameters: temperature (28.96±0.28oC), dissolved oxygen (5.6±0.13mg/l), pH (6.73±0.19) and conductivity (159.8±0.32μS/cm) measured were within suitable standard ranges for fish production in natural waters. A total of 16 species from 10 families were identified from the lake. Cichlids had the highest number of fish species (4) and relative abundance (66.82%) and Coptodon zillii was the most abundant fish species across the months and sampling stations (27.53%). The lower section of the lake had the highest relative abundance (52.90%) while the upper section of the lake had the least (16.14%) and the highest fish catch (13.35%) was in November. The species richness of the lake decreased from lower (S=16) to upper section (S=14), the middle section was highly diversified (H=0.73) with a combined value of H=0.67 for the lake. The fish species were evenly distributed across the lake with the highest evenness in the upper section (E=0.22). Simpson’s index was highest in the lower region (D=0.30) and there was a high probability of picking different fish species at random. Trophic grouping showed forage to carnivore (F/C) ratio of 2.06 indicating an unbalanced fish population based on food habit, which should be addressed. There is need for proper regulation such as enforcement of fishing seasons and fishing across the trophic levels to ensure sustainability of the fish resources in the lake

Application of the Marketing School of Thought and Their Implications in Nigeria Market:A Study of Music Industry

The schools of marketing thoughts have received scholarly attention from marketing enthusiasts and academics from related disciplines such as Economics, Psychology and Sociology. Several works have been published by scholars in an attempt to explain away the schools of marketing thoughts. Some writers traced development of marketing by time period, a few focused on specific marketing thoughts while others simply concentrated on reviewing history of individual schools of marketing thought. Such is the varied and diverse nature of these classifications that it could be somewhat confusing to an average reader. There is the great need to understand the varied classification, as well as the development of each school of thought, its primary focus and contributors to each school. This paper, therefore, seeks to contribute to this discourse by undertaking an archival survey of the extant literature to identifying theories and models relating to the concepts and philosophies of marketing schools of thought. The objective of this study is basically to examine the application of the theoretical foundations and ideas of marketing schools of thought to the music industry in Nigeria. Findings by the study reveals that with the increasing popularity of music industry in Nigeria and the application of the schools of marketing thought, there is need for proper planning, supportive structure and government intervention, of the industry. It is hereby recommended that it is imperative for the government to sponsor and legislate on laws that advance the development of music industry in Nigeria

An Undergraduate Control Tutorial on Root Locus-Based Magnetic Levitation System Stabilization

The subject of control system design has evolved considerably over the years. Although several design techniques and strategies have been adopted to realize control systems that meet a predetermined set of performance criteria, the fundamental problem remains that of developing controllers to adjust the performance characteristics of a dynamic system in order to obtain a desired output behavior. The dynamic behavior of a magnetic levitation system (MLS) of a ferromagnetic ball is compensated in this paper. Consolidating the exposure of undergraduate students to the rudiments of control system design, the paper employs the classical root locus technique to stabilize the system. A combination of analytical and software-based methods is used to design proportional-derivative and phase-lead compensators based on the linearized model of the system. Complete details of the design approach, from modeling and analysis of the plant to computing the values of the controller parameters, are shown. MATLAB scripts for plotting root loci and simulating the system are provided

Report of Mixed Infection of Infectious Bursal Disease and Chicken Infectious Anaemia Viruses

Infectious bursa disease (IBD) was tentatively diagnosed from an experimental cockerel flock. Clinical signs observed included dullness, diarrhoea characterized by greenish yellow colour and spiking mortality lasting four days. Post-mortem examination results showed pale and slightly enlarged liver and kidney, enlarged and haemorrhagic bursa, petechia haemorrhages on the spleen, keel and thigh muscles and thymus atrophy. Pale liver, thymus atrophy and haemorrhages in the bursa could also be presented in Chicken Infectious Anaemia (CIA) infection. The organs (Bursa, kidney, thymus and liver) from where the infected birds were further screened for IBD and CIA viruses using the polymerase chain reaction technique and were positive for both. This confirms IBD and CIA are responsible for the losses in the flock. This implies that many CIA infections or its mixed infection may be mistaken for IBD alone if no confirmatory diagnosis is carried out, since most post-mortem lesions presenting extensive syndrome are considered to be caused by IBD. &nbsp

Mechanical Behaviour and Microstructural Characterization of Carbon Steel Samples from Three Selected Steel Rolling Plants

The research investigated the mechanical behavior of samples of steel rods obtained from three selected Steel Rolling Companies in South Western part of Nigeria. This was done by carrying out some mechanical tests such as tensile, impact and hardness as well as microstructural examination.Four sets of 16 mm steel rod samples were collected from Tiger steel industries, Phoenix steel and Oxil steel Industies, all located in South West Nigeria, The chemical composition was carried out using a Spectrometer (EDX3600B). Afterwards, different samples were prepared, cut and machined according to ASTM standards dimensions of tensile and impact tests as well as hardness test from which their Ultimate tensile Strength, Yield strength, Percentage elongation, Impact strength and Brinell hardness number were obtained and compared to three standards (ASTM A706, BS 4449 and Nst 65-Mn). Their microstructures were also examined and analyzed.The results showed that the Ultimate tensile strength for the samples from Oxil steel, Phoenix Steel and Tiger steel were 661 N/(mm)2, 653 N/(mm)2 and 631 N/(mm)2 respectively while their hardness values were 150 BHN, 178 BHN, 214 BHN respectively. The sample from Tiger steel and Oxil Steel had the finest and most coarse microstructure respectively. In conclusion, it was observed that the results of the sample analysis from the three selected Steel Rolling Companies conformed to most of the standards except the sample from Tiger steel which had a high hardness value compared to the standard

Effect of drinking magnetized water on immunity and carcass quality of broiler chicken

This study was conducted to determine the effect of drinking Magnetized Water (MW) on the immunity of broiler chicken. The problem which this study focused on was the mortality rate of broiler chicken which is common in some poultry farms in Nigeria due to some factors that could lead to loss of income. There is a need for economical methods for boosting the immunity of Broiler Chicken (BC) in order to reduce the mortality rate. BC (Arbor Acres breed) was given MW. The magnetized water was produced by passing water through the magnetic field in a pipe. The treatments were MW treated for 33s by passing the water through pipe surrounded with magnets one time(T1), MW treated for 66 s by flowing twice through the magnetic unit (T2), T3 was MW treated for 99 s and control (Non-Magnetized Water, NMW, T0). A total of 80 BCs (day old) with 20 BC for each treatment were given MW (T1, T2 and T3), NMW and monitored for 7 weeks. Blood samples were collected for hematology and analyzed using standard methods. The values of white blood cell for T0, T1, T2 and T3 were 153.61×10-9/L, 133.20×10-9/L, 134.78×10-9/L and 101.12×10-9/L and for lymphocytes, were 137.08×10-9/L, 120.79×10-9/L, 125.49×10-9/L and 96.12×10-9/L, respectively. MW T1, T2 and T3 increased body weight gain of the BC by 410, 320 and 210g/broiler. Protein contents of the carcass for T1, T2, T3 and T0 were 13.13%, 13.23%, 13.18% and 12.80%, respectively. MW can therefore enhance production of healthy broiler chickens