860 research outputs found
Emulsion-Liquid-Membrane Extraction of Alkali Metals by Nano-baskets
Nano-assisted inclusion separation of alkali metals from basic solutions was reported by inclusionfacilitated
emulsion liquid membrane process. The novelty of this study is application of nano-baskets of
calixcrown in the selective and efficient separation of alkali metals as both the carrier and the surfactant.
For this aim, four derivatives of diacid calix[4]-1,3-crowns-4,5 were synthesized, and their inclusionextraction
parameters were optimized including the calixcrown scaffold (4, 4 wt%) as the carrier/
demulsifier, the commercial kerosene as diluent in membrane, sulphonic acid (0.2 M) and ammonium
carbonate (0.4 M) as the strip and the feed phases, the phase and the treat ratios of 0.8 and 0.3, mixing
speed (300 rpm), and initial solute concentration (100 mg/L). The results reveled that under the optimized
operating condition, the degree of inclusion-extraction of alkali metals was as high as 98-99%.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3513
Voltammetric Behavior of Nano-basket Complexes
Eight nano-baskets of cone calix[4]arene-crown-3, -crown-4, -crown-5, -crown-6 were synthesized and
their binding abilities towards alkali and alkaline earth metals as well as some lanthanides were studied
using differential pulse voltammetry. The novelty of this study was investigation of those nano-basket
complexes by voltammetric behaviors of two acidic moieties in each scaffold during complexation of crown
ether ring. Their voltammetric behaviors were closely related to the complex formation by entrapment of
cation into crown ether cavity and ion-dipole interaction between cation and acidic moieties in nanobaskets.
The results revealed the selective changes in voltammetric behavior of synthesized scaffolds toward
the cations. By increasing the binding ability of macrocycle and cation, the anodic oxidation peak of
carboxylic acids was decreased. It was shown that the voltammetric traces of low energy complexes did not
affected by encapsulated cations in the coordination space of crown ether and they showed no voltammetric
behavior.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3546
Liquid-Liquid Microextraction of Tetrahedral Oxoanions by Nano-baskets
This paper introduces a nano-based microextraction and examines its ability in preconcentration of dinegative
tetrahedral oxoanions in the produced water. Nano-baskets of diacid p-tert-butylcalix[4]arene in
the cone conformation were synthesized and used. The related parameters including ligand concentration,
volume of water disperser, salt effect, and extraction time were optimized. The linear range, detection limit
(S/N 3) and precision (RSD, n 6) were determined to be in the range of 1.0–280, 2.0–42.0 μgL−1 and 2.6–
11.0 %, respectively.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519
Inclusion Chromatography of Albuterol in Livestock by Nano-baskets
Albuterol, which increases the muscle mass and decreases the adipose tissue, is misused as nutrient
repartitioning agent in livestock. Hence, a new sensitive method for determination of albuterol in livestock
is presented. Four nano-baskets of calix[4]crown were synthesized and used to prepare nano-based bendedphases
of HPLC–UV. The new synthesized bonded-phases were characterized and optimized, the bonding
interactions of solute:stationary phases were examined and the main interactions were reported. The albuterol
level of six samples of livestock meat including pork, pork casing, beef, beef casing, mutton, and
mutton casing were analyzed and the results revealed that for the best bonded-phases, the LOD and LOQ
were 0.06 and 0.20 μg/mL, respectively.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3495
Metabolic Fingerprinting of Rat Serum by Nano-baskets and ELM – NMR
A novel approach for metabolite extraction and fingerprinting was introduced base upon the emulsion
liquid membrane-nuclear magnetic resonance (ELM – NMR) technique. The objective of this method is optimizing
the fingerprints, minimizing the metabolic variation from analysis, increasing the likelihood differences,
and obtaining the maximum extraction yield. Low molecular weight metabolites in rat serum
were recovered by ELMs using four nano-baskets of calix [4]-1,3-crowns as emulsifier and carrier. The
yields of ELMs were optimized by the method of once at a time. According to the NMR data, the maximum
metabolic variation was achieved using scaffold 4 (4 wt %), n-decane membrane, stirring rate of 300 rpm,
treat and phase ratios of 0.3 and 0.8, respectively. According to the NMR data, the results revealed that calixcrowns
1-3 tend to extract non-specific macromolecules and the repeatability of fingerprints for 4-
mediated ELM was more than three others. The yield of extractions was obtained to be higher for n-decane
and lower for carbon tetrachloride. Using different membrane types, the fingerprints by chlorinated liquid
membranes were more repeatable than toluene or n-decane.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3496
Voltammetric Behavior of Nano-basket Complexes
Eight nano-baskets of cone calix[4]arene-crown-3, -crown-4, -crown-5, -crown-6 were synthesized and
their binding abilities towards alkali and alkaline earth metals as well as some lanthanides were studied
using differential pulse voltammetry. The novelty of this study was investigation of those nano-basket
complexes by voltammetric behaviors of two acidic moieties in each scaffold during complexation of crown
ether ring. Their voltammetric behaviors were closely related to the complex formation by entrapment of
cation into crown ether cavity and ion-dipole interaction between cation and acidic moieties in nanobaskets.
The results revealed the selective changes in voltammetric behavior of synthesized scaffolds toward
the cations. By increasing the binding ability of macrocycle and cation, the anodic oxidation peak of
carboxylic acids was decreased. It was shown that the voltammetric traces of low energy complexes did not
affected by encapsulated cations in the coordination space of crown ether and they showed no voltammetric
behavior.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3546
Liquid-Liquid Microextraction of Vanadyl Porphyrins by Nano-baskets
The novelties of this approach are introducing the self-settled dispersive liquid-liquid microextraction
technique to remove the centrifuging step, conducting the dispersive liquid phase microextraction in complex
organic systems, applicability of water as disperser phase, and nano-extraction of charged porphyrins
by nano-baskets of calixcrown, which act as the settling agents as well as the inclusion ligands. Four proton
di-ionizable diacid conformers of 25,26-bis(carboxymethoxy)calix[4]arene-27,28-crown-3; -crown-4; -
crown-5; and -crown-6 in the cone conformation were synthesized and used. The related parameters including
ligand concentration, volume of water disperser, salt effect, and extraction time were optimized. The
linear range, detection limit (S/N 3) and precision (RSD, n 6) were determined to be 0.2–50, 0.07 μgL−1
and 5.3%, respectively. The established method was applied to determine the target compound in five
samples of live crude oil, were sampled from an Iranian offshore field. Owing to the overall differences
(such as organic media, inclusion extraction, water-soluble ligands, etc), the comparison of the proposed
method with the traditional liquid-liquid microextraction was inapplicable. These results revealed that the
new approach is competitive analytical tool and an alternative of the traditional methods in the crude oil
and related systems.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519
Stakeholder-driven multi-attribute analysis for energy project selection under uncertainty
In practice, selecting an energy project for development requires balancing criteria and competing stakeholder priorities to identify the best alternative. Energy source selection can be modeled as multi-criteria decision-maker problems to provide quantitative support to reconcile technical, economic, environmental, social, and political factors with respect to the stakeholders' interests. Decision making among these complex interactions should also account for the uncertainty present in the input data. In response, this work develops a stochastic decision analysis framework to evaluate alternatives by involving stakeholders to identify both quantitative and qualitative selection criteria and performance metrics which carry uncertainties. The developed framework is illustrated using a case study from Fairbanks, Alaska, where decision makers and residents must decide on a new source of energy for heating and electricity. We approach this problem in a five step methodology: (1) engaging experts (role players) to develop criteria of project performance; (2) collecting a range of quantitative and qualitative input information to determine the performance of each proposed solution according to the selected criteria; (3) performing a Monte-Carlo analysis to capture uncertainties given in the inputs; (4) applying multi-criteria decision-making, social choice (voting), and fallback bargaining methods to account for three different levels of cooperation among the stakeholders; and (5) computing an aggregate performance index (API) score for each alternative based on its performance across criteria and cooperation levels. API scores communicate relative performance between alternatives. In this way, our methodology maps uncertainty from the input data to reflect risk in the decision and incorporates varying degrees of cooperation into the analysis to identify an optimal and practical alternative
Advanced risk management in offshore terminals and marine ports
This research aims to propose a Risk Management (RM) framework and develop a generic risk-based model for dealing with potential hazards and risk factors associated with offshore terminals' and marine ports' operations and management. Hazard identification was conducted through an appropriate literature review of major risk factors of these logistic infrastructures. As a result in the first phase of this research a Fuzzy Analytical Hierarchal Process (FAHP) method was used for determining the relative weights of the risk factors identified via the literature review. This has led to the development of a generic risk -based model which can help related industrial professionals and risk managers assess the risk factors and develop appropriate strategies to take preventive/corrective actions for mitigation purposes, with a view of maintaining efficient offshore terminals' and marine ports' operations and management. In the second phase of the research the developed risk-based model incorporating Fuzzy Set Theory (FST), an Evidential Reasoning (ER) approach and the IDS software were used to evaluate the risk levels of different ports in real situations using a case study. The IDS software based on an ER approach was used to aggregate the previously determined relative weights of the risk factors with the new evaluation results of risk levels for the real ports. The third phase of the research made use of the Cause and Consequence Analysis (CCA) including the Fault Tree Analysis (FTA) and Event Tree Analysis (ETA) under a fuzzy environment, to analyse in detail the most significant risk factors determined from the first phase of the research, using appropriate case-studies. In the fourth phase of the research an individual RM strategy was tailored and implemented on the most significant risk factor identified previously. In the last phase of the research and in order to complete the RM cycle, the best mitigation strategies were introduced and evaluated in the form of ideal solutions for mitigating the identified risk factors. All methods used in this research have quantitative and qualitative nature. Expert judgements carried out for gathering the required information accounted for the majority of data collected. The proposed RM framework can be a useful method for managers and auditors when conducting their RM programmes in the offshore and marine industries. The novelty of this research can help the Quality, Health, Safety, Environment and Security (QHSES) managers, insurers and risk managers in the offshore and marine industries investigate the potential hazards more appropriately if there is uncertainty of data sources. In this research with considering strategic management approaches to RM development the proposed RM framework and risk based model contribute to knowledge by developing and evaluating an effective methodology for future use of the RM professionals
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