Search results for " solution"
showing 10 items of 3084 documents
LFER and the Effect of Temperature on Oxyanion Adsorption by Goethite
2019
A linear relationship between the Gibbs free energy, ΔGr,H+, of the aqueous complex deprotonation reaction, and the Gibbs free energy, ΔGr,ads, of bidentate surface complexation reaction of oxyanions was derived from modelling of temperature dependent batch equilibrium adsorption experiments. As exemplified in this study, this relationship may be exploited to predict temperature-dependent adsorption behavior of oxyanions not yet known such as pertechnetate.
Use of metallurgical dust for removal chromium ions from aqueous solutions
2018
The aim of the study was to determine the potential for the application of dust from steel plant as an effective sorbent for removing Cr(III) and Cr(VI) in the form of simple and complex ions – Acid Blue 193 dye from aqueous solutions. Three isotherms models were used to interpret the experimental results namely: Langmuir, Freundlich, and Dubinin–Radushkevich. Estimated equations parameters allowed to determine the binding mechanism. Based on laboratory studies it was found that the dust was characterized by high sorption capacities for Cr ions and dye from the aqueous solution. The sorption capacity of the dust for Cr(III) and Cr(VI) ions depended on the degree of oxidation, pH of solution…
The Influence of Urban Agglomeration on the Accumulation of Certain Heavy Metal Ions in Tansy (Tanacetum vulgare L.)
2020
Different compounds including toxic heavy metals ions have been used in various industrial branches for ages. Therefore, these compounds are nowadays often identified in the natural environment. Plants usually function like indirect transporters through which heavy metals, in the form of ions, infiltrate from the environment into the human and animals’ food chains. The present paper studied the influence of urban agglomeration on the accumulation of certain heavy metals in tansy. The content of heavy metals ions (Cr, Ni, Cd and Pb) was marked in the tansy leaves. Depending on the location of sampling, large variations in the heavy metal content were observed in the plant material. The resea…
COMPARATIVE STUDY OF THE DECISION-MAKING PROCESS IN SMES AND IN LARGE COMPANIES
2012
This article presents the importance of the decisional act in the entrepreneurial process, trying to emphasize its implications in various situations faced by managers and decision factors. Starting with the classic definition of the “decision” concept, this paper extends its meaning by applying it on the economic field and by deepening its meaning in the economic field, shaping the imperative requests a decision has to make. Narrowing the research field to the sphere of small and medium-sized enterprises, the analysis of the decision is made on their level, being built on the antithesis SME- large company. The results of the study consist in the appreciation of the importance the decision …
Towards the Learning Experience Technology Usability framework
2017
The availability of learning technology has increased over past decades; however, severe usability issues that cause adverse effects on the learning experience can be found in many available technologies. Learning solution usability is commonly evaluated by focusing on either technical or pedagogical usability and rarely both. This artificially separates the two important aspects of learning technology usability. This chapter provides a new framework for designing and evaluating learning solutions that synthesizes the above usability types to consider them a part of a complex and dynamic whole comprising of learning, technological design, content-related issues and context. The proposed Lea…
Spectroscopic and Structural Investigation of the Confinement of D and L Dimethyl Tartrate in Lecithin Reverse Micelles
2009
The confinement of D and L dimethyl tartrate in lecithin reverse micelles dispersed in cyclohexane has been investigated by FT-IR, polarimetry, electronic and vibrational circular dichroism (ECD and VCD), 1H NMR, and small-angle X-ray scattering (SAXS). Measurements have been performed at room temperature as a function of the solubilizate-to-surfactant molar ratio (R) at fixed lecithin concentration. The analysis of experimental data indicates that the dimethyl tartrate molecules are solubilized within reverse micelles in proximity to the surfactant head groups in the same way for the D and L forms. The encapsulation of dimethyl tatrate within lecithin reverse micelles involves changes in i…
Dictamen profesional sobre la fusión y escisión como extrategias alternativas en un grupo de sociedades
2021
This work is a professional, legal opinion which sets out two alternative strategies (merger by absorption and partial demerger) in order to bring together the different areas of activity of the various companies in a group of companies. The aim is to provide solutions to the questions raised by customers and, therefore, to set out clearly and simply the procedure to be followed in each of the strategies, weighing up the advantages and disadvantages from each of them
Life-based design for technical solutions in social and voluntary work
2012
The Social and Voluntary work sector operates outside the organised boundaries and systems of normal business, financial and government organisational institutions. My target during this research has been to develop an optimum solution for decision support towards committing and accepting resources in the Social Work and Voluntary sector. In initial part of this monograph, I have traced the history of Design Thinking from the time it was ‘art and craft’ until modern times where multiple approaches are tried, tested and implemented for solution development. For the actual application development, I have chosen the Life-based Design conceptual framework. Three design iterations were made in t…
Liquid Phase Micro-Extraction of Linear Alkylbenzene Sulfonate Anionic Surfactants in Aqueous Samples
2011
Hollow fiber liquid phase micro-extraction (LPME) of linear alkylbenzene sulfonates (LAS) from aqueous samples was studied. Ion pair extraction of C10, C11, C12 and C13 homologues was facilitated with trihexylamine as ion-pairing agent, using di-n-hexylether as solvent for the supported liquid membrane (SLM). Effects of extraction time, acceptor buffer concentration, stirring speed, sample volume, NaCl and humic acids were studied. At 10–50 µg L−1 linear R2-coefficients were 0.99 for C10 and C11 and 0.96 for C12. RSD was typically ~15%. Three observations were especially made. Firstly, LPME for these analytes was unusually slow with maximum enrichment observed after 15–24 h (depending on sa…