Parameterization of Teacher-made Physics Achievement Test Using Deterministic-Input-Noisy-and-Gate (DINA) Model

Traditional methods of test parameterization have been found defective in terms of assuming one score and not providing information on skills mastery profile of the examinees, in addition to non-estimation of the fourth parameter- slipping parameter of test items. Cognitive diagnostic modeling (CDM), specifically deterministic-input-noisy-and-gate (DINA) model is a robust procedure for measuring the skills mastery profile of the examinees, when there is no attribute hierarchy. DINA model also estimates four item parameters: discriminating, difficult, guessing and slipping which hitherto are not implemented as a whole in traditional techniques including the item response theory (IRT). Physics was chosen because it is commingled with civilization. Also, secondary school Physics teachers predominantly use teacher-made tests in their internal examinations in Nigeria.  Such instrument cannot be used to precipitate the true ability levels of the students for purposes of promotion. The data collected plus the harmonized Q-matrix were analyzed using CDM package in r software version 3.4.3 via R-Studio version 1.0.153. The results showed that: (i) eighteen items in the test fit the DINA model while thirty-two items had misfit. (ii) nine attributes were mastered by the examinees while three attributes were not mastered. It was recommended that schools’ item banks should be created by the governments for uploading psychometrically robust test items for teachers’ use. Keywords: Physics, teacher-made test, DINA model and parameterization

Nutritional Status, Care Giving And Feeding Practices Of Infant And Pre-School Children (0 - 5 Years) In Motherless Babies Homes In Owerri Metropolis

The study was conducted to determine the nutritional status, care-giving and feeding practices of infants and preschool children (0-5 years) in the motherless babies home (Red Cross and Holy family sisters of the Needy motherless Babies Home) in Imo State. A cross sectional survey was carried out to elicit information from 100 respondents who were randomly selected. Statistical package for social sciences (SPSS) version 16 was used to analyze the data. The World Health Organization Classification was used to define the anthropometric analysis such as wasting, stunting and underweight among the children. Result revealed that anthropometric measurement using WHO standards used in defining the following: Weight- for - height which showed that 18% were wasted, height-for-age assessment revealed that 34% were stunted and weight-far-age showed that 19% were underweight while 19% of the children were overweight. The result of the study indicate that 19% of children were breastfed by wet nursing, 7%  ate > 2 times daily, 11% take fits 3 times per week the health status of the children showed that 19% of them were sick all the time, 2% each of the children had Oedema and Beriberi, 26 % had scurvy, 11% had rickets while 37% of the children had anaemic look on them. In conclusion, the study revealed that the nutritional status of the infants and preschool children in the motherless babies home is generally low due to the children's poor feeding habit and poor nutrition knowledge of the care givers as indicated by the study. Keywords: Nutritional Status, Care Giving, Feeding Practices,  Infant, Pre-School Children, Motherless Babies Hom

A maximum power point tracking scheme for a 1kw stand-alone solar energy based power supply

This paper elucidates one of the tracking schemes for a photovoltaic (PV) systems using Cuk converter operating in discontinuous inductor current mode (DICM) as an interface. A method for efficiently maximizing the output power of a solar panel supplying a load or battery bus under varying meteorological conditions is investigated and results presented therein. The incremental conductance (InCond) method of maximum power point tracking (MPPT) using the Cuks dc to dc converter operating in a discontinuous inductor current mode (DICM) was modeled and studied in relation to PV system interface. Also, laboratory setup was implemented based on the model. This was the main objective of the research. Similarly, the PV simulator was also modeled alongside with Cuk converter operating in DICM. MATLAB/SIMULINK software was used to carry out simulation test. With the incremental conductance method, the problem of sustained oscillation around the maximum power point of the solar panel which is the usual characteristic of the perturbation and observation method is essentially absent. The result disclosed that the power available for the load when MPPT was applied was 1.1 kW which gives a tolerance of 0.1% to the load it powers. But without MPPT, the available power is 0.9 kW using the same number of PV panels and batteries as back up. Hence, MPPT has 17.65% edge in power delivery over non-MPPT PV powered energy supply. An experimental prototype of a 1kW, 230V, 50Hz stand-alone solar based power supply with the incremental conductance scheme was successfully implemented using PIC 16F877 microcontroller, tested and results presented therein. The experimental results agreed with the simulated results.Keywords: Maximum Power point tracking, Cuk converter, Photovoltaic system, PIC 16F877A micro-controller, inverter, batteries

Evaluating The Perception of Climate Change Among Secondary School Science Teachers for Knowledge-Based Sustainable Development

There appears to be lack of knowledge about the cause and effect of climate change amongst the secondary school students. This asks for evaluation of their source of knowledge in schools through the assessment of their teachers’ knowledge and/or perception about climatic change. The survey research design was adopted and the perception of the secondary school science teachers’ (SSSTs) evaluated using questionnaire. The results showed that SSSTs perception of human activities associated with climate change and the effects of human activities associated with climate is moderate. This was very clear when the grand mean responses of the teachers were found to be 2.81 and 2.61 respectively. The student t-test statistics used at P>0.05 confirmed that there is no significant difference between the perception of urban and rural SSSTs on their perception of climate change. At P>0.05, there is significant difference between experienced and less experienced SSSTs on their perception of climate change.  The research concludes that there is knowledge gap in our secondary school educational system concerning climate change. Therefore, it recommends capacity building in science-teaching education curriculum for knowledge-based sustainable development. Keywords: Curriculum, Global warming, Environmental Education, Greenhouse gases, Deforestation DOI: 10.7176/CER/13-5-03 Publication date:August 31st 2021

Steady State Analysis Of Single Phase IPM Motors By D-Q Harmonic Balance Method

A concise steady-state analysis of a single-phase line-start permanent magnet (SPLSPM) machine is conducted from a developed d-q model using the d-q harmonic balance technique. The d-q model was developed in rotor reference frame from a phase variable model of the machine. SPLSPM whose performance indices were characterized by high torque ripples has detailed analysis docile mostly in computer simulations quite unlike the three-phase types. The main cause is not far-fetched, it was due to nonexistence of precise mathematical model in d-q rotor frame of the motor due to the unbalanced field winding, the rotor saliency and the presence of the capacitor in the auxiliary windings. Even after model has been developed, the simple traditional procedure of setting all time varying component to zero for steady-state analysis fails because the rotor position dependence on the inductance expressions could not be eliminated. The d-q harmonic-balance technique was then applied. An important feature of the harmonic balance technique was that it decoupled all equations to simple sine waveforms in a style that resembled Fourier series. Results yield torque pulsation, current and load characteristics in the steady state

Potential antidiabetic and antioxidant activities of a heliangolide sesquiterpene lactone isolated from Helianthus annuus L. Leaves

Heliangolide is a naturally occurring sesquiterpene lactone and its derivatives are biologically active compounds present in most medicinal plants. This study evaluated the antioxidant and antidiabetic properties of a heliangolide sesquiterpene lactone isolated from Helianthus annuus L. leaves. The heliangolide sesquiterpene lactone was isolated through combination of solvent-solvent partitioning, column chromatography, thin layer chromatography and high performance-liquid chromatography techniques. The antioxidant activity of the compound was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide radical scavenging assays while the antidiabetic effects were investigated in alloxan-induced diabetic rats. The heliangolide derivative at 954.2 µmol L–1 showed 23.7 % DPPH and 26 % nitric oxide radical inhibitions compared with 96.6 and 50.9 %, resp., displayed by the controls (2,271.2 µmol L–1). It also reduced the fasting blood glucose (FBG) levels in a time-dependent manner. The highest activity was recorded within 6 h post-treatment at 0.2 mmol kg–1 bm. The heliangolide derivative exhibited significant (p < 0.05) antioxidant and antidiabetic properties and provides basis for further development of constituents of Helianthus annuus leaves for the management of such diseases

Development of a software solution for solar-PV power systems sizing and monitoring

Power systems sizing and monitoring are very important design components in determining the overall performance of solar-photovoltaic (PV) systems. These design components represent the pre-installation and post-installation stages of solar-PV systems planning respectively, and paying adequate attention to them can go a long way to increasing the working life of solar-PV system installations. The SolarHelper developed in this work is a small software solution package that monitors and records vital system variables that will give the state and performance of an existing solar-PV installation at any given time; and it is able to accurately provide a simulated output of the required battery storage capacity, and PV array size based on load demands

Socio-Economic Determinants of Academic Performances in Aguata Local Government Area, Anambra State

Education is regarded as the greatest investment that any nation can make for the development of its human and material resources. This paper investigated the socio-economic determinants of academic performance in Aguata local government area, Anambra state. The study made use of a qualitative response regression model to analyze the participant’s responses obtained through a well-structured questionnaire. The study presents some interesting findings. The ML-Binary logit estimation results show that parental income (PI); number of hours of study (NHS); parent educational achievement (PEA) and power supply (PS) have positive and significant impact on student’s academic performance (AP), family size (FS) has a negative and significant impact on student’s academic performance (AP) whereas residential area (RA) has positive and insignificant impact on academic performance. The correlation results show that all the variables except family size are positively correlated with student’s academic performance. The study therefore recommends that since parental income is a very important variable which influences student’s academic performance; government employment initiatives should be strengthened while those that are not effective should be reviewed. Government’s effort to boost power supply should be intensified beyond mere transfer of ownership to the private sector. Epileptic power supply does not augur well with the academic performances of students as the finding of this study has shown. Key words: Education, Academic performance, Anambra State. JEL Classification: P17, H4, H

Assessment of the Implications of Coal Post-mining Impact on Surface Water at Abandoned Okpara mine in Enugu State

This study examines the coal post-mining impact on surface water at abandoned Okpara mine in Enugu State. Experimental research design was adopted to test the water quality. The water samples were collected and analysed to determine the level of pollution. Hhypotheses were tested using analysis of variance (ANOVA) and the treatment means were separated using Duncan’s multiple range test (DMRT). The result of the test of hypothesis one shows that there is no significant difference in the parameters of the water samples within months. For all the parameters, α-significant at P≤0.05 fall within .207 and .995. DMRT shows that with the exception of temperature, that there is significant difference in other parameters of the water samples collected at different stations. For the parameters, alpha (α) is significant at P≤0.05. The result also shows that with the exception of Lead (Pb), that there is significant difference (p≤0.05) in the heavy metals found in the water samples collected at different stations. The total viable count (TVC) of the bacteria Pseudomonas aurogenosa and Bacillus substilis were 9.0×103cfu/ml and 1.2×104cfu/ml for the month of July, while in the month of August it was 9.0×103cfu/ml and 1.3×104cfu/ml respectively. The study concludes that the abandoned coal mine sites contribute to the type of microorganisms found in the water and concentration of heavy metals present in the water samples as well as other physicochemical parameters/indicators of water quality. Keywords: Coal post-mining, Water quality, Microbial load, Pollution, Trace metals DOI: 10.7176/JEES/11-4-08 Publication date: April 30th 202