ZnO: SnO2 nanocomposite efficacy for gas sensing and microbial applications

586-594The unique characteristics of 2-dimensional hetero structure offers efficient gas sensing with high selectivity to identify gases from the interference gases which is quite difficult. In the present work, ZnO: SnO2Nano composite clusters (NCC) is prepared. A resistive metal oxide volatile organic compound (VOC) gas sensor is fabricated with nullifying the effect of humidity by increasing temperature optimally. A single-step SOL-GEL (SG) synthesis is used to prepare ZnO: SnO2 NCC with maximum Zn/Sn molar concentration ratio of 3. The morphological studies through Scanning Electron Microscopy (SEM), electrical properties due to oxygen vacancies and energy band variations of Nanocomposite are measured. The enhancement of gas sensor sensitivity due to highly mesoporous nature of the composite is observed. From the findings, the abundant mesopores in the range of 2 nm-14 nm and specific surface area of 54.2 m2 g−1 with the average crystal size of 14.236 nm, and polar surface area of the composite 25.9651Åis achieved. When compared to bare ZnO and SnO2 gas sensors, the present gas sensor offers the higher selectivity with enhanced performance due to the mesoporous structure. Fast repeatability rate of 2200 sec at 350C to ethanol is attained and the overall selectivity of the sensor increased twice as 2.085. The NCC compound is tested firstly with micro organisms such as B. subtilis (B. S), Bacillus cereus (B. C), B.coagulans (B. C), Pseudonymous auriginosa (P. A) are considered for antimicrobial activity. From the findings, zincstannate compound showed good efficacy towards B. cereus Gram positive and P.A gram-negative. A bacterial growth isarrested highly with B. cereus

Perception of teachers about classroom assessment and self-perceive of teachers' competency in classroom assessment

This study investigated on teachers’ perception about classroom assessment and self-perceive of teachers’competency in classroom assessment. Purpose of this study is to find out significant mean differences between teachers’ competency in classroom assessment based on academic qualification, professional qualification, experience in teaching, experience in constructing classroom assessment and experience in attending assessment related courses. A total 367 teachers were drawn from Johor Bahru District secondary schools using sampling frame provided by Johor Bahru district education Office to be the respondents of the study. Sample size of this study was selected using formula to determine sample size as suggested by Israel. Reseacher has used random sampling to select respondents for the study. The study used a questionnaire which has Alpha Cronbach value 0.95 to establish teachers’ perceptions about classroom assessment and Alpha Cronbach value 0.85 for self-evaluation of teachers’competency in constructing classroom assessment. Part A of the questionnaire contained 8 items related to demography of the respondents. Part B(i) consists of 15 items related to teachers’perception about classroom assessment answered by respondents using agreement type Likert Scale and Part B (ii), consists 40 items about self-evaluation of teachers’competency in constructing classroom assessment answered by the respondents using frequency type Likert scale. Research question 1 and 2 were answered using descriptive analysis using statistical test frequency, mean and percentage whereby research questions 3 to 7 were answered using inferential analysis using statistical test one-way ANOVA. Hypotheses null 1 to 5 were analysed using One Way ANOVA and Post Hoc Test. Findings research question 1 indicated that teachers have positive perception about classroom assessment with mean = 4.01 which was high. Findings on research question 2 about teachers’ competency in constructing classroom assessment based on six constructs namely planning classroom assessment (mean = 3.77); constructing classroom assessment 9 (mean = 3.69); assembling classroom assessment ( mean score: 3.81); administering classroom assessment (mean = 3.8); scoring classroom assessment (mean = 3.77) and appraising classroom assessment (mean = 3.72) indicated that teachers in Johor Bahru District Secondary schools have high competency in administering and assembling classroom assessment, whereby they have least competency in constructing and appraising classroom assessment. Analysis on hypotheses null indicated that there was significant mean difference between teachers’ competency in classroom assessment based academic qualification (F=2.772, p< .041). Post Hoc test revealed that teachers who have bachelor degree and masters degree (sig.= .041) as their academic qualification have the highest competency in classroom assessment compared to teachers with diploma and certificate (sig.= .998) as their academic qualification. Researcher has suggested further researches related to the study to fulfill the aspration of Ministry of Education in producing more competent teachers especially in measurement and evaluation

Response of crop seeds towards the leaf leachates of Parthenium hysterophorus L.

This article does not have an abstract

ZnO: SnO2 nanocomposite efficacy for gas sensing and microbial applications

The unique characteristics of 2-dimensional hetero structure offers efficient gas sensing with high selectivity to identify gases from the interference gases which is quite difficult. In the present work, ZnO: SnO2Nano composite clusters (NCC) is prepared. A resistive metal oxide volatile organic compound (VOC) gas sensor is fabricated with nullifying the effect of humidity by increasing temperature optimally. A single-step SOL-GEL (SG) synthesis is used to prepare ZnO: SnO2 NCC with maximum Zn/Sn molar concentration ratio of 3. The morphological studies through Scanning Electron Microscopy (SEM), electrical properties due to oxygen vacancies and energy band variations of Nanocomposite are measured. The enhancement of gas sensor sensitivity due to highly mesoporous nature of the composite is observed. From the findings, the abundant mesopores in the range of 2 nm-14 nm and specific surface area of 54.2 m2 g−1 with the average crystal size of 14.236 nm, and polar surface area of the composite 25.9651Åis achieved. When compared to bare ZnO and SnO2 gas sensors, the present gas sensor offers the higher selectivity with enhanced performance due to the mesoporous structure. Fast repeatability rate of 2200 sec at 350C to ethanol is attained and the overall selectivity of the sensor increased twice as 2.085. The NCC compound is tested firstly with micro organisms such as B. subtilis (B. S), Bacillus cereus (B. C), B. coagulans (B. C), Pseudonymous auriginosa (P. A) are considered for antimicrobial activity. From the findings, zinc stannate compound showed good efficacy towards B. cereus Gram positive and P.A gram-negative. A bacterial growth is arrested highly with B. cereus

Classroom assessment: do teachers have the required competencies?

This study investigated teachers' perceptions and competency in classroom assessment, and also examined mean differences on teachers' competency based on academic qualification, teaching experience and assessment training. A total of 367 teachers has been selected using random sampling technique among secondary schools in city zone Johor Bahru District. This study employed a survey design using a set of questionnaire consisted of 40 items with Likert Scale 5 point and value of Alpha Cronbach.90. Data were analyzed using descriptive (frequency, percentage, mean and standard deviation) and inferential statistical analysis (one way ANOVA). The findings showed that teachers have positive perception about classroom assessment (M=3.73; SD=.80) and overall teachers' competency in constructing classroom assessment (M=3.76; SD=1.04), where for planning (M=3.77; SD=.89), constructing (M=3.73; SD=.94), assembling (M=3.81; SD=.97), administering (M = 3.89; SD=1.42), scoring (M=3.77; SD=1.02) and item analysis (M= 3.56; SD=1.02). The study also found a significant mean difference on academic qualification (F=2.772,

Synthesis, structural, thermal, mechanical, laser damage threshold and DFT investigations on bis (2-methylimidazolium-4-aminobenzoate) single crystal

An organic salt, bis (2-methylimidazolium-4-aminobenzoate) (MIAB) was synthesized and single crystals grown successfully by slow solvent evaporation solution growth technique using ethyl acetate as solvent at room temperature. Fourier transform infrared (FTIR) spectral analysis was carried out to detect the presence of functional groups in the MIAB salt crystal. H-1 and C-13 spectra were recorded to confirm the presence of various kinds of proton and carbon environments thereby establish the molecular structure of MIAB crystal. Single crystal X-ray diffraction analysis (SCXRD) reveal that the crystal belongs to monoclinic system centrosymmetric space group, P2(1/)c. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) confirms that the MIAB crystal is thermally stable up to 250 degrees C. The mechanical properties of the grown crystal were determined by Vickers Microhardness test. Computational studies were performed using Gaussian 09 software by 6.31 g basis set level. The calculated first order hyperpolarizability (beta) of MIAB from computational studies is 5.01 times that of Potassium dihydrogen phosphate (KDP). The laser damage threshold value of the MIAB is found to be 1.44 GW/cm(2). Z-scan technique reveals the optical non-linearity of the crystal