Estimating Reliability on Tests with dichotomous and Polychromous Items According to the classical Theory of Measurement and Generalizability Theory: A Comparative Study

This current study aimed to compare reliability coefficients on tests with dichotomous and polytomous items according to classical theory of measurement and generalizability theory, to achieve this, a compound ability test was constructed in mathematics in two forms: Dichotomous and Polytomous by using five estimation methods, which as follows: (Alpha {α}, Theta{θ}, Raju, {G}, and {φ}), Furthermore, in order to achieve the study objectives, the test was applied on two forms, each test consists of 30 items to measure students mathematical ability on the field of numbers, Algebra, Geometries and Statistics, to 300 of the sample study. the reliability coefficients of the Dichotomous and estimated according to the Classical theory on the following manner: (α= 0.87, θ= 0.85, Raju= 0.86), and according to the Generalizability theory (G= 0.87, φ= 0.86), hence, the counter coefficients of Polytomous according to the Classical theory (α= 0.95, θ= 0.92, Raju= 0.93), and according to the Generalizability theory (G= 0.95, φ= 0.94).). The results of the comparison between the coefficients according to the Cocron test and the signal/noise ratio test showed that there was a significant difference at (α =0.05) between the reliability coefficients values of the ability test on its two forms in favor of the polytomous, and the results also revealed a preference for generalizability theory in the estimation of reliability coefficients as extracted to classical coefficients

Investigation of the New Room Temperature Ionic Liquid of Al(NO3)3.9H2O with Urea CO(NH2)2

Mixing aluminum nitrate nonahydrate with urea produced room temperatures clear colorless ionic liquid with lowest freezing temperature at (1: 1.2) mole ratio respectively. Freezing point phase diagram was determined and density, viscosity and conductivity were measured at room temperature. It showed physical properties similar to other ionic liquids. FT-IR,UV-Vis, 1H NMR and 13C NMR were used to study the interaction between its species where - CO ??? Al- bond was suggested and basic ion [Al(NO3)4]? and acidic ions [Al(NO3)2. xU]+ were proposed. Water molecule believed to interact with both ions. Redox potential was determined to be about 2 Volt from – 0.6 to + 1.4 Volt with thermal stability up to 326 ?

312 MAX Phases: Elastic Properties and Lithiation

Interest in the Mn+1AXn phases (M = early transition metal; A = group 13–16 elements, and X = C or N) is driven by their ceramic and metallic properties, which make them attractive candidates for numerous applications. In the present study, we use the density functional theory to calculate the elastic properties and the incorporation of lithium atoms in the 312 MAX phases. It is shown that the energy to incorporate one Li atom in Mo3SiC2, Hf3AlC2, Zr3AlC2, and Zr3SiC2 is particularly low, and thus, theoretically, these materials should be considered for battery applications

Quantitative structure-toxicity relationship study of some natural and synthetic coumarins using retention parameters

Four lipophilicity descriptors (RM0, b, C0, PC1) for twelve coumarine derivatives were determined by reversed-phase thin-layer chromatography in order to analyze which descriptor best describes the lipophilicity of coumarines investigated. Moreover, possible chemical toxicity of coumarins, expressed as the probability of a compound to cause organ-specific health effects, was calculated using ACD/Tox Suite program. The quantitative relationships between toxicity and molecular descriptors, including experimentally determined lipophilicity descriptors obtained in current study, were investigated using partial least square regression. The best models were obtained for kidney and liver health effects. Quantitative structure-toxicity relationship models revealed the importance of electric polarization descriptors, size descriptors and lipophilicity descriptors. Obtained models were used for the selection of the structural features of the compounds that are significantly affecting their absorption, distribution, metabolism, excretion, and toxicity. [Acknowledgements. This work has been supported by the Ministry of Education and Science of Serbia, Grant 172017.

A robust 3D finite element model for concrete columns confined by FRCM system

Fibre reinforced cementitious matric (FRCM) is a recent application of fibre reinforced polymer (FRP) reinforcement, developed to overcome several limitations associated with the use of organic adhesive [e.g. epoxies] in FRPs. It consists of two dimensional FRP mesh saturated with a cement mortar, which is inorganic in nature and compatible with concrete and masonry substrates. In this study, a robust three-dimensional (3D) finite element (FE) model has been developed to study the behaviour of slender reinforced concrete columns confined by FRCM jackets, and loaded concentrically and eccentrically. The model accounts for material nonlinearities in column core and cement mortar, composite failure of FRP mesh, and global buckling. The model response was validated against several laboratory tests from literature, comparing the ultimate load, load-lateral deflection and failure mode. Maximum divergence between numerical and experimental results was 12%. Following the validation, the model will be used later in a comprehensive parametric analysis to gain a profound knowledge of the strengthening system, and examine the effects of several factors expected to influence the behaviour of confined member

Frequency of inter- and intraventricular dyssynchrony in patients with heart failure according to QRS width

Aims: Cardiac resynchronization therapy (CRT) is an effective treatment for heart failure patients with prolongation of QRS duration. Despite careful patient selection, some do not respond to CRT based on QRS complex duration. We sought to evaluate the presence of left ventricular dyssynchrony using tissue Doppler imaging (TDI) according to QRS duration in heart failure patients. Methods and results: Ninety-nine patients (mean age 52.6 ± 15.3 years) with severe heart failure left ventricular (LV) ejection fraction, 40 ms and intra-LV mechanical delays (defined as Ts-SD >33.4 ms and Ts-diff >100 ms) were correlated with the QRS width and morphology. We found a greater IVMD in Group II patients, compared with patients in Group I (42.5 ± 22.3 vs. 26.8 ± 21, respectively, P 40 ms. Conclusion: A substantial proportion of patients with prolonged QRS (32.1%) did not exhibit inter- or intraventricular dyssynchrony, which may represent a limitation in identifying the ideal QRS interval for the selection of patients for CRT. © The Author 2007

Antibacterial Evaluation of Some Schiff Bases Derived from 2-Acetylpyridine and Their Metal Complexes

A series of Schiff bases derived from 2-acetylpyridne and their metal complexes were characterized by elemental analysis, NMR, FT-IR and UV-Vis spectral studies. The complexes were screened for anti-bacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumanni (AC), Klebsiella pneumonie (KB) and Pseudomonas aeruginosa (PA) using the disc diffusion and micro broth dilution assays. Based on the overall results, the complexes showed the highest activities against MRSA while a weak antibacterial activity was observed against A. baumanii and P. aeruginosa

Elaboration and characterisation of novel low-cost adsorbents from grass-derived sulphonated lignin

AbstractThis study investigated the use of water-soluble sulphonated lignin (SL) extracted from grass, which has not been used before as a precursor of activated carbon (AC). Chemical activation of SL with three dehydrating salts (ZnCl2, KCl, Fe2(SO4)3·xH2O) at various salt concentrations (10%, 20%, 30%w/w), charring temperatures (600,700°C) and charring times (1,2h) has been carried out. The surface characteristics and removal efficiencies of cadmium, copper and zinc ions from aqueous solutions were affected by the activation conditions. The sulphonated lignin-based activated carbons (SLACs) with the highest specific surface area, total pore and micropore volume were produced at the lowest dehydrating salt concentration (10%w/w) and at 700°C and 2-h charring. These optimal sulphonated lignin-based ACs were named SLAC-ZC (optimal grass-derived SLAC activated by zinc chloride); SLAC-PC (optimal grass-derived SLAC activated by potassium chloride) and SLAC-FS (optimal grass-derived SLAC activated by ferric sulphate). The central composite design and surface response methodology of different SLACs characteristics showed that the optimal responses were achieved at the same operating conditions. These SLACs also achieved the highest removal efficiencies of Cd2+, Cu2+ and Zn2+ ions from aqueous solutions. The chemical activation had significantly increased the total porosity, microporosity and surface area of water-soluble SL. The activation mechanism depended on the used dehydrating salt where the porosity developed by the dehydration effect of ZnCl2, and by a series of hydrolysis and redox reactions for the other two salts. The results of this research demonstrated that water-soluble SL has a great potential as a novel precursor for the production of activated carbons