Chromium speciation using an aminated amberlite XAD-4 resin column combined with microsample injection-flame atomic absorption spectrometry

Amberlite XAD-4 resin (AXAD-4) was chemically modified to an aminated Amberlite XAD-4 (AAXAD-4) resin and characterized by infrared spectroscopy. AAXAD-4 resin was used as an efficient solid phase for the preconcentration and speciation of Cr(III) and Cr(VI) ions by column technique. The concentration of chromium species was determined by microsample injection system-flame atomic absorption spectrometer (MIS-FAAS). Selective retention of Cr(III) ions was achieved at pH 8.0 and eluted using 1.0 mL of 3.0 mol L–1 HCl and 1.0 mL of 2.0 mol L–1 NaOH, successively, at the flow rate of 5.0 mL min–1. The maximal sorption capacity of AAXAD-4 resin for Cr(III) ions was found to be 67.0 mg g–1. The limit of detection (LOD) and limit of quantitation (LOQ) for Cr(III) ions were found to be 0.041 and 0.131 µg L–1, respectively, with preconcentration factor (PF) of 375 and relative standard deviation (RSD) of 3.75% (n = 11). The method was validated using certified reference materials (CRMs) and successfully applied to the real samples, spiked with Cr(III) and Cr(VI) ions. © 2018 Slovensko Kemijsko Drustvo. All rights reserved

Cooling Water Discharge Impacts to an Ephemeral Stream: a Heat Transport Modeling Study

Integrated Modeling of Hydro-System

SME’S Rating System and Process in Turkey According to the Basel II Settlements

Basel II settlements have a strong influence on the SMEs that are of great importance to countries’ economies. Conditions to become an SME have changed and rating of SMEs has become very important with this new settlement. In this study, in order to be awarded high credit ratings SMEs will be evaluated by analyzing this period in accordance with Basel II. The following were studied; the rating period and its requirements under the framework of Basel II, rating of SMEs and the criteria used during this period, credit rating analysis methods under the scope of the rating procedure and principle

Geometric explanation of anomalous finite-size scaling in high dimensions

We give an intuitive geometric explanation for the apparent breakdown of standard finite-size scaling in systems with periodic boundaries above the upper critical dimension. The Ising model and self-avoiding walk are simulated on five-dimensional hypercubic lattices with free and periodic boundary conditions, by using geometric representations and recently introduced Markov-chain Monte Carlo algorithms. We show that previously observed anomalous behaviour for correlation functions, measured on the standard Euclidean scale, can be removed by defining correlation functions on a scale which correctly accounts for windings.Comment: 5 pages, 4 figure

The development of a universal and cultural values scale for values education

The aim of the study reported on here was to develop a universal and cultural values scale (UCVS) to measure the universal and cultural values to be incorporated in primary education. The items measured were derived from an item pool prepared with expert consultation. The study was conducted with 360 fifth-grade students who attended primary schools in Istanbul during the 2018–2019 academic year. The construct validity of the scale was determined with exploratory and confirmatory factor analyses. The internal consistency obtained for the whole scale was reasonably strong (α = 0.81). The utility of the scale as a valid and reliable measure for use in determining elementary school students’ attitudes toward universal and cultural values is discussed. Keywords: scale development; universal and cultural values; values; values education; values scal

Lifted Worm Algorithm for the Ising Model

We design an irreversible worm algorithm for the zero-field ferromagnetic Ising model by using the lifting technique. We study the dynamic critical behavior of an energy estimator on both the complete graph and toroidal grids, and compare our findings with reversible algorithms such as the Prokof'ev-Svistunov worm algorithm. Our results show that the lifted worm algorithm improves the dynamic exponent of the energy estimator on the complete graph, and leads to a significant constant improvement on toroidal grids.Comment: 9 pages, 6 figure

The configurational effects of task‑technology fit, technology‑induced engagement and motivation on learning performance during Covid‑19 pandemic: An fsQCA approach

At the onset of 2020, Covid-19 pandemic began and disrupted teaching and learning activities with substantial implications for resources and operations. Against this backdrop, the configural causal effects of task-technology fit, technology-induced engagement and motivation, gender, and residential location on learning performance are examined. The proposed association was tested with a dyad sample of faculty members and students (n = 16) using fuzzy sets (fsQCA) analysis. Results show that (i) task-technology fit, and technology-induced motivation emerge as necessary conditions for high learning performance; (ii) task-technology fit, technology-induced engagement and motivation are sufficient conditions for high learning performance among female students, (iii) task-technology fit, technology-induced engagement and motivation are sufficient conditions for high learning performance among students living in urban areas and (iv) task-technology fit is a sufficient condition for high learning performance among female students living in rural areas irrespective of technology-induced engagement and motivation. Implications for theory and policy prescriptions are offered for practitioners.No sponso

Sorbent extraction of some metal ions on a gas chromatographic stationary phase prior to their flame atomic absorption determinations

An enrichment/separation system for atomic absorption spectrometric determinations of Cu(II), Fe(III), Ni(II) and Co(II) has been established. The procedure is based on the adsorption of the analytes as calmagite chelates on Chromosorb-102. The effects of some parameters including pH, amount of ligand, salt matrix, flow rates of sample and eluent solutions were investigated. Under optimized conditions, the relative standard deviation of the combined method of sample treatment, preconcentration and determination with FAAS (N=5) is generally lower than 5%. The limit of detection (3σ) was between 6.0-112. 9 μg/L. The results were used for preconcentration of analytes from some sodium and ammonium salt