PRELIMINARY MULTIDOMAIN MODELLING AND SIMULATION STUDY OF A HORIZONTAL AXIS WIND TURBINE (HAWT) TOWER VIBRATION

Renewable energy sources have gained much attention due to the recent energy crisis and the urge to get clean energy. Among the main options being studied, wind energy is a strong contender because of its reliability due to the maturity of the technology, good infrastructure and relative cost competitiveness. It is also interesting to note that there are physical limits to the potential height of a wind turbine tower since the mechanical structure of wind turbines are thus very flexible and tend to oscillate. This makes the design of wind turbines a demanding task. In this paper, the oscillation of a wind turbine tower due to imbalance in the masses of the blades is modeled in maplesim and the effect of the tower height on its oscillation was simulated. For a wind turbine with three rotor blades, two of which have masses of 10 kg, a mass moment of inertia of approximately 20 kg/m2 and one of the blades has a moment of inertia which is 1% less than the other blades. The simulation showed the most stable system for the most energy capture for this case study to be a rotor speed of 5.5rad/s at a height of 10m. At this angular frequency the deflection of the top of the wind turbine was approximately 1mm.  http://dx.doi.org/10.4314/njt.v36i1.1

Factors influencing self-employment intention among Nigerian post-graduate students of Universiti Utara Malaysia (UUM)

Report shows that more than 60% of young individuals below 30 years of age are interested in owning their own business. However, only a small number of students start a business immediately after graduation due to the fact that being an entrepreneur is not considered as a career option. This study seeks to examine the relationship between entrepreneurship education, entrepreneurial experience and societal entrepreneurship attitude as factors influencing self-employment intention. The study was theoretically based on the Theory of Planned Behavior (TPB), Social Cognitive Theory (SCT) and Social Cognitive Career Theory (SCCT). Self-administered survey method was used to distribute questionnaire for collecting primary data through a simple random sampling technique from 113 Nigerian postgraduate students of Universiti Utara Malaysia (UUM) who are active in status. The collected data were then analyzed. The findings of this study found that entrepreneurship education, entrepreneurial experience and societal entrepreneurship attitude are positively related to UUM’s Nigerian postgraduate student’s intention towards self-employment. The study provides an enriched contribution to knowledge and significant implication to the theory and practices of entrepreneurship. It also signaled to policy makers such as education authority as well as government to look into the effect of entrepreneurship education, prior entrepreneurship experience as well as societal entrepreneurship attitude as influencing factors on students’ intention of becoming self-employed

Cross cultural adaptation dimensions and demographic factors of international students in UUM

The number of international students in Malaysian universities have been increasing over the years. The international students come from many different countries and thus from a diverse cultural background. Thus, they had to adapt and adjust to the different cultural aspects of the Malaysian way of life. This study examined the differences between cross cultural adaptation dimensions and demographic factors (age, gender, marital status, study period and working experiences) that influence international students. A survey on 335 international students of Universiti Utara Malaysia was carried out to obtain the data for the study. The usable responses of 251 were analyze using SPSS version 22 involving descriptive statistic, anova and t-test. The result reveal there are no significant differences of age on cross cultural adaptation dimensions, but for gender, marital status, study period and work experience indicate significant differences for either one or two of the cross- cultural adaptation dimensions. This study revealed that there are many issues faced by the international students in UUM. The issues are related to the cross-cultural adaptation dimension and demographic factors among international students in UUM. Thus, it is recommended that there is a need to form an interaction among management and international students in the form of activities or programs to boost the cross-cultural adaptability of these students. This will enable the students to attain the necessary skills that will enhance their adaptability to the local context. Finally, implications, limitations of the study, and conclusion were also highlighted

Growth effects of government expenditure in Nigeria: Does the level of corruption matter?

A strand of literature suggests that an efficient government can complement private capital formation and boost the overall productivity of private economic agents. Nigeria has experienced uneven growth performance in the last three decades despite growing government expenditure. This paper carried out an empirical analysis of direct and indirect links among growth, government expenditure and corruption in Nigeria using annual time series data for the period from 1990 to 2020. The autoregressive distributed lag (ARDL) model was used to explore the long-run interacting effect of corruption on the nexus between growth and government expenditure. For the robustness check, the fully modified ordinary least squares (FMOLS) and dynamic ordinary least squares (DOLS) were used as alternative techniques of estimation. Directly, an increase in government expenditure and a reduction in corruption has a significant increasing effect in the short-term and long-term growth. Indirectly, reducing corruption enhances the increasing effect of government expenditure on economic growth. However, corruption reduction up to the 42.25 threshold and beyond diminishes the increasing effect of government expenditure on economic growth. This suggests that attaining sustained growth is possible by raising government expenditure and minimizing corruption. Thus, minimizing corruption associated with expenditure policy should be a top policy priority

An assessment of the microbiological quality of some bottle water sold in Kano metropolis, Nigeria

Bottled water like any drinking water used for human consumption should be safe and of standard quality to ensure adequate public health significance. The aim of the study is to assess the quality of some bottle water sold in Kano Metropolis and compare the result with some national and international standards. Studies on the microbiological parametric standards, was conducted. A total of 40 samples comprising of 4 different brands were randomly selected using stratified sampling techniques from different sites of Kano metropolis in northern Nigeria. Samples were analyzed for the presence of bacterial indicators of water quality using pour plate and MPN techniques. The result of Total aerobic Plate counts (APC) ranged from 2.06x102 -3.8x102 cful/ml of the entire brand. All the bottled water brands had a mean (APC) greater than 100cfu/ml of bottled water standard. Total coliform and Eschericia coli were detected in two brands and were above the zero cfu/ per 100milliter of bottled water standard. No pathogenic bacteria were isolated except forStaphylococcus. Effective implementation of WHO water safety plans from the catchment source to the consumer through campaign awareness can reduce level of exposure to stake holders to protect and store bottle water against sunlight exposure, chemicals and cleaning reagents.Key words: Quality, Bottled water, Kano Metropoli

Analysis of Water Quality for Domestic use in Lafia Town, Nasarawa State, Nigeria

Lafia is a town in the middle belt of Nigeria located within Latitude 8 25W and 8 35W and Longitudes 8 28 E and 8 34 E Lafia covers an area of about 258km2 and has a population of about 330 712 inhabitants This population caused environmental pollution as a result pressures exerts on the available water sources It is against this background that this study is carried out to analyze the water quality for domestic use in Lafia town with the aim of examining the water quality status of the area compared to the World Health Organization permissible guidelines for portable water The method adopted involves the use of reconnaissance survey Data were collected from both primary and secondary sources and subjected to descriptive and laboratory analysis The result shows that stream water source is the most polluted in Lafia with colour concentration of 10 5pt co turbidity of 8 5NTU and temperature of 26 4 c The chemical properties for all the water sources sampled were slightly above the World Health Organization permissible guidelines The result also shows that none of the water sources met the permissible guidelines in terms of chemical and microbiological properties It was recommended amongst others that Nasarawa state water board should be provided with modern facilities for efficient address of domestic water use in Lafia Clear water for everyone in Lafia for sustainable developmen

Determining house price for mass appraisal using multiple regression analysis modeling in Kaduna North, Nigeria

The research applied Multiple Regression Analysis (MRA) in estimating house price for mass appraisal in Kaduna north, Nigeria. Two basic micro determinants of house price were considered, namely; structural attributes and location of property. Using a sample of 106 house sale transactions data which were recorded between 2011 to 2015, MRA was used to determine the structural variables and locational attributes that have statistically significant influence on the house price. It was found that among the variables included in the MRA, year of transaction, type of house, availability of swimming pool, availability of security post, type of door and location of the property were significant in determining house price in Kaduna. However, number of bedroom, number of living room, type of ceiling, condition of the house were not significant in influencing house price. Using the significant variables, a mass appraisal model was developed for the study area. The performance of the model was evaluated using the ratio study method and the model was found to be satisfactory. It was recommended that, this model be used in mass appraisal of residential properties in Kaduna north in the future, with a view to improve accuracy, objectivity, efficiency, and fairness of the property taxation system, which will lead to generating more revenue for the government and, encourage physical infrastructural development in Kaduna North.Keywords: Mass Appraisal, Multiple Regression Analysis (MRA), House Price, Valuatio

Profitability Analysis of Three Methods of Suya Production and Marketing in Maiduguri metropolitan Council, Borno State, Nigeria

The study determined the economics of alternative methods of Suya production and marketing in Maiduguri Metropolitan Area in Borno State of Nigeria. Data were obtained from 108 respondents using questionnaire and oral interview schedule. Descriptive statistics, the gross margin, Ginni coefficient, market margin and average cost function were used as analytical tools. The findings of the study indicate that the three major types of Suya in the study area were Tsire, Balangu and Kilishi. Estimated gross margin per kilogram of meat used in preparation of Kilishi, Balangu and Tsire were N150, N 32 and N 114, respectively. The returns to labour were N 3.13, N 1.95, N 2.2 for Kilishi, Balangu and Tsire producers, respectively. The returns to other variable costs were 29 kobo for Kilishi and Tsire producers and 1 kobo for Balangu producers. The benefit-cost ratios were estimated as N 1:27:1. N 1.25:1 and N 1.1:1 for Kilishi, Tsire and Balangu production and marketing enterprises, respectively. The marketing margins for Kilishi, Tsire and Balangu were estimated as37.45%, 43.39% and 21.56%, respectively. Analysis of the market structures shows that all the Suya types were differentiated and market knowledge imperfect. The Ginni coefficients for Tsire and Balangu Suya types were similar (0.5), with many producers and buyers and relatively free entry into the market, depicting monopolistic competitive structure. In addition to differentiated products and imperfect market knowledge, Kilishi market had a Ginni Coefficient of 0.2, few producers and buyerswith restricted freedom of entry, typical of oligopolistic competition. There is absence of scale economics in the three types of Suya study. Based on the findings of the study it was recommended that all Suya products should be registered with National Agency for Food and Drug AdministrativeControl (NAFDAC) for quality programme to ensure good sanitation of the meat products.Keywords: Suya, marketing, Maiduguri, Borno Stat

The Impact of some Meteorological Variables on the Estimation of Global Solar Radiation in Kano, North Western, Nigeria

This study examines the impact of measured monthly average daily global solar radiation, sunshine duration, wind speed, maximum and minimum temperatures, rainfall, cloud cover and relative humidity parameters on the estimation of global solar radiation during the period of thirty one years (1980 – 2010) for Kano, Nigeria (Latitude 12.030N, Longitude 08.120E and altitude 472.5 m above sea level) using different selected proposed empirical models. The accuracy of the proposed models are tested using statistical indicator; Mean Bias Error (MBE), Root Mean Square Error (RMSE), Mean Percentage Error (MPE), t – test, correlation coefficient (R) and coefficient of determination (R2). The developed models are based on one variable correlation, two variable correlations, three variable correlations, four variable correlations, five variable correlations and six variable correlations, in each case one or two empirical models has been recommended based on their outstanding performance in line with the statistical test subjected to. The model (Eqn. 36) with the highest values of R and R2 and lowest values of MBE, RMSE, MPE and t – test as compared with other developed model is considered the best performing model. It was observed that the newly recommended developed models (Eqns. 13, 17, 21, 26, 27, 31, 35 and 36) can be used for estimating daily values of global solar radiation with higher accuracy and has good adaptability to highly changing climatic conditions for Kano and regions of similar climatic information. Keywords: global solar radiation, sunshine duration, wind speed, rainfall and coefficient of determination