Internal Model Loss Minimization Control of Permanent Magnet Synchronous Machine

Electric drives are very useful in propelling the wheels of hybrid electric vehicles (HEVs). They also play a central function in the electric power steering (EPS). This paper describes studies carried out on the efficiency optimization of an interior permanent magnet synchronous machine (IPMSM) for application in the EPS. An analytic loss- minimization algorithm for an IPMSM was derived and the optimization problem took into consideration copper, iron and stray losses. The proposed loss minimization algorithm is simple and cost effective to implement. From the simulations carried out, significant efficiency gains are possible with this model. The internal model control (IMC) method was employed to achieve current and speed control with acceptable sensitivity to machine parameters

Chest X-ray findings in HIV- infected Highly Active Antiretroviral Treatment (HAART) - naïve patients

Introduction: Patients with human immunodeficiency virus (HIV) infection frequently present with a wide spectrum of pulmonary and cardiaccomplications from the virus, opportunistic infections and neoplasms that may be associated with a high mortality rate. Diseases of the respiratorytract account for about half of deaths from AIDS, while cardiac diseases account for more than a quarter of deaths from AIDS. This study aimed atdetermining the prevalence of pulmonary and cardiac diseases using a chest radiograph in HAART-naïve HIV-infected patients. Methods: Thisstudy was conducted at Lagos State University Teaching Hospital (LASUTH) HIV clinic between September 2010 and August 2011 amongst allregistered HAART-naïve HIV/AIDS patients. Patients had posterior-anterior chest radiographs done in full inspiration. Participants were asked andaided to fill the structured questionnaires to obtain demographic data. Results: Out of a total of one hundred and two recruited for the study, 54 (52.94%) had a normal chest radiograph, while 48 (47.06%) had abnormal chest radiograph .The abnormal findings included, 27.45% who hadbronchopneumonia, 6.86% cardiomegaly, 5.88% pulmonary tuberculosis, 5.88% radiological features of congestive cardiac failure, and 0.98%bronchitis. Conclusion: It appears that more than half of HAART–naïve HIV-infected patients have normal chest radiographs. Bronchopneumonia(27.5%) is the commonest pulmonary abnormality associated with HIV infection, while the prevalence of pulmonary tuberculosis is 5.88%.Key words: Chest X-ray, HIV-infected, HAART-naïve

Impact of Electromagnetic Field on Bacterial Population and Physicochemical Properties of Cassava Wastewater

The release of industrial wastewaters into the environment is a major source of toxic contaminants causing global health and environmental challenges. This study aimed to investigate the impact of electromagnetic field (EMF) treatment on bacterial population and physicochemical characteristics of cassava wastewater. Cassava wastewater sample was collected from point source of a small-scale cassava industry in Akure, Nigeria. Sample was thereafter treated with EMF of varying intensities (70- 130nT) and bacterial population and physicochemical properties of raw and treated wastewater sample were determined using standard microbiological, physical and chemical analytical techniques. Results revealed a total bacterial count of 1.34 x 105cfu/ ml. Identity of bacterial genera isolated from wastewater were Enterobacter aerogenes, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi (Gram negative) while the Gram positive bacteria were Staphylococcus aureus, Bacillus cereus, Bacillus subtilis and Lactobacillus sp. Results also revealed that treatment of wastewater sample with EMF significantly reduced the bacterial load and physicochemical parameters of the sample and dependent on EMF intensity and duration of exposure. Results revealed a decline in bacterial population from 1.34 x 105- 1.0 x 104 at intensities of 70nT-130nT and exposure time of 0- 144hr with the lowest count obtained at 130nT and the highest at 70nT. This study concludes that the use of Electromagnetic Field holds promise as an effective, non-invasive and eco-friendly strategy to improve the physical, chemical and biological quality of wastewater before discharge into the environment

ADAPTING MODERN METHODS OF LECTURING IN NIGERIAN UNIVERSITIES: A CRITIQUE

Different disciplines have explored the concept of lecturing from different perspectives. However, adapting some modern methods of lecturing in Nigerian universities have not been systematically studied.   Therefore, this paper examines critically the modern   methods of lecturing in our modern days tertiary institutions in Nigeria.In agreement with other researches, this paper notes that there are many challenges facing the   methods of teaching in Nigerian Universities today. Triangulation method was used to gather information for this paper, and both primary and secondary   sources were used to obtain information for this article.  The findings of this paper show that the traditional lecture method will not lead to much educational achievements unless it is combined with interactive engagements with the students and prompt feedback from the tutorsThe paper recommends that if Government could live up to her   expectation by provision of basic amenities and   state-of-the-arts teaching facilities to the tertiary institutions, the phenomenon could be reduced. A concerted effort is therefore needed among all stake holders in the education sector for the task of promoting effective teaching in our tertiary institutions

Statistical Properties of the Exponentiated Generalized Inverted Exponential Distribution

We provide another generalization of the inverted exponential distribution which serves as a competitive model and an alternative to both the generalized inverse exponential distribution and the inverse exponential distribution. The model is positively skewed and its shape could be decreasing or unimodal (depending on its parameter values). The statistical properties of the proposed model are provided and the method of Maximum Likelihood Estimation (MLE) was proposed in estimating its parameters

Radioactivity Measurements of the Jos Tin Mine Tailing in Northern Nigeria

The activity concentrations of 226Ra and232Th in Jos Tin mine tailings and its environment were measured using Hyper-pure Germanium detector (HPGe). Preset counting time of 30,000s was used for each sample to avoid statistical errors. Results showed the activities varied from one site to another. The activities of 226Ra and232Th are much higher than the recommended average limit given by UNSCEAR in the mining sites and even at 500 m away from the mining site. At 1 Km away from the mining site the activity measured is within the limit for normal background. The ratio of activity of Thorium to Radium is greater by factor of 5 in all the samples in the mining site and 500 m away which should be about unity. The mean absorbed doses (1828.66, 252.08 and 171.07 nGyh-1) for Site1, Site2 and 500m from mining site respectively in air are equally high compared with (51 nGyh-1). Also, the estimated effective dose equivalents are much higher than the recommended limit except for 1 Km from the mining site. There is need to improve waste management practices in this industries in order not to expose those living and working in this environment to health hazards associated with these radionuclide

Evaluation of kinetic parameters of traps in thermoluminescence phosphors

A method for evaluating trap depth E, order of kinetics b and frequency factor s from a thermoluminescence (TL) glow peak has been developed. The method is based on using intensities and temperatures at any three points on the glow peak. Unlike similar techniques that provide no expression for frequency factor, the present formulation provides such an expression. The expression does not require knowledge of the temperature at which maximum intensity occurs, a parameter not usually known accurately from experimental glow peak data. For the method, it is found that use of points in the ascending part of the glow peak where the intensities are less than 10% maximum intensity gives parameter values closest to the true ones. Possible reasons for getting less accurate results when points are taken beyond this region are discussed. Values of the activation energy calculated using the present technique were always close to the true value. However, the frequency factor only approaches the true value as the dose given to the sample approaches saturation. When the three data points are selected in the initial-rise region, the equation for evaluating E in the method described in this paper becomes a two-point version of the initial-rise method. The advantage of the present technique over the initial-rise method is that it also gives b and hence s. The method is used to analyse the TL glow curve of a gamma-irradiated sample from Ijero-Ekiti, Nigeria

On A New Weighted Exponential Distribution: Theory and Application

A new two-parameter weighted exponential distribution which has more mild algebraic properties than the existing weighted exponential distribution was studied. Explicit expressions for some of its basic statistical properties including moments, reliability analysis, quantile function and order statistics were derived. Its parameters were estimated using the method of maximum likelihood estimation. The new probability model was applied to four real data sets to assess its flexibility over the existing weighted exponential distributio

SCREENING FOR HEAVY MOLECULAR WEIGHT HYDROCARBON UTILIZING BACTERIA FROM OIL IMPACTED, NON OIL IMPACTED SOIL AND NATURAL DEPOSITS

Control and treatment of hazardous effects of heavy molecular weight oil (bitumen) pollution are essential in contaminated soil. This study involved the isolation and screening of microorganisms capable of utilizing heavy molecular weight hydrocarbon from oil impacted, non oil impacted soil and natural deposits of bitumen. Total heterotrophic bacterial counts in the samples ranged from 1.4 ªª? 105 CFU/g to 2.0 ªª? 106 CFU/g. Total oil utilizing bacterial counts varied from 1.5 ªª? 104 CFU/g to 3.6 ªª? 105 CFU/g. Isolates were identified using API 20E kit. They belong to the genera Burkholderia, Pseudomonas, and Serratia. Degradation efficiency of the isolates on Premium Motor Spirit (PMS), Dual Purpose Kerosene (DPK) and Low Pour Point Fuel Oil (LPFO) were carried out by a colorimetric rapid screen test using 2, 6-dichlorophenol indophenol (DCPIP) reduction test which was monitored by measuring absorbance at 600 nm at every 24 hrs for 120 hrs. Order of ability of the isolates to degrade PMS: P. aeruginosa > P. mendocina > P. borbori > S. rubidae > P. cichorii > B. cepacia while for DPK is P. cichorii > P. borbori > S. rubidae > P. mendocina > B. cepacia > P. aeruginosa. Ability to degrade LPFO: P. cichorii > P. borbori > P. aeruginosa > P. mendocina > B. cepacia > S. rubidae.ª¤

On A New Weighted Exponential Distribution: Theory and Application

A new two-parameter weighted exponential distribution which has more mild algebraic properties than the existing weighted exponential distribution was studied. Explicit expressions for some of its basic statistical properties including moments, reliability analysis, quantile function and order statistics were derived. Its parameters were estimated using the method of maximum likelihood estimation. The new probability model was applied to four real data sets to assess its flexibility over the existing weighted exponential distributio