Search results for "OPERATION"
showing 10 items of 2969 documents
Potential of phosphonium-based ionic liquids to purify 1-propanol from water by liquid–liquid extraction at mild conditions
2022
Abstract In order to reduce the environmental of the separation of 1-propanol from water in a residual industry stream for its reuse, the capability as solvents of two different trihexyl(tetradecyl)phosphonium ionic liquids (ILs) – trihexyl(tetradecyl)phosphonium chloride ([TDTHP][Cl]) and trihexyl(tetradecyl)phosphonium bromide ([TDTHP][Br])-, was studied. The liquid–liquid equilibria data for both ternary systems, {water + 1-propanol + [TDTHP][Cl]} and {water + 1-propanol + [TDTHP][Br]} at different mild work temperatures, (283.2, 303.2 and 323.2) K, and atmospheric pressure were measured. The thermodynamic parameters for both ternary systems at different work conditions were obtained by …
Prediction of Maxwell – Stefan diffusion coefficients in polymer – multicomponent fluid systems
2014
Abstract Calculations of mass fluxes in multicomponent fluids based on the system of generalized Maxwell–Stefan equations (GMSE) is preferably used because Maxwell–Stefan (M–S) diffusion coefficients are symmetrical and have a clear physical meaning, as they reflect the binary friction forces between compounds in the system. For the calculation of the mass transport of a multicomponent fluid in the polymer basing on GMSE, it is necessary to have M–S diffusion coefficients. This paper proposes a method that allows their calculation using widely available self-diffusion coefficients and binary diffusion coefficients for infinitely diluted mixtures. The proposed method was compared with the me…
Phase equilibrium for the systems diisopropyl ether, isopropyl alcohol+2,2,4-trimethylpentane and +n-heptane at 101.3kPa
2010
Abstract Consistent vapour–liquid equilibrium data for the ternary systems diisopropyl ether + isopropyl alcohol + 2,2,4-trimethylpentane and diisopropyl ether + isopropyl alcohol + n-heptane are reported at 101.3 kPa. The vapour–liquid equilibrium data have been correlated by Wilson, NRTL and UNIQUAC equations. The ternary systems do not present ternary azeotropes.
Phase Equilibria Involved in Extractive Distillation of Dipropyl Ether + 1-Propyl Alcohol Using N,N-Dimethylformamide as Entrainer
2007
Consistent vapor−liquid equilibrium data for the binary and ternary systems dipropyl ether (1) + 1-propyl alcohol (2) + N,N-dimethylformamide (3) are reported at 101.3 kPa. The results indicate that dipropyl ether (1) + N,N-dimethylformamide (3) system exhibits a positive deviation from ideal behavior and that 1-propyl alcohol (2) + N,N-dimethylformamide (3) system deviates negatively from ideality. The activity coefficients of the solutions were correlated by the Wilson, NRTL, and UNIQUAC models. It is shown that these models allow a very good prediction of the phase equilibrium of the ternary system using the pertinent parameters of the binary systems. In addition, the Wisniak−Tamir relat…
Contingent claim valuation in a market with different interest rates
1995
The problem of contingent claim valuation in a market with a higher interest rate for borrowing than for lending is discussed. We give results which cover especially the European call and put options. The method used is based on transforming the problem to suitable auxiliary markets with only one interest rate for borrowing and lending and is adapted from a paper of Cvitanic and Karatzas (1992) where the authors study constrained portfolio problems.
Value preserving portfolio strategies and the minimal martingale measure
1998
We consider some relations between the minimal martingale measure and the value preserving martingale measure in a continuous-time securities market. Under the assumption of continuous share prices we show that under a structure condition both these martingale measures exist and indeed coincide. This however does not mean that the corresponding concepts of value preserving portfolio strategies and (local) risk minimisation in the area of option hedging in incomplete markets are identical.
Adaptive memory programing for the robust capacitated international sourcing problem
2008
The International Sourcing Problem consists of selecting a subset from an available set of potential suppliers internationally located. The selected suppliers must meet the demand for items from a set of plants, which are also located worldwide. Since the costs are affected by macroeconomic conditions in the countries where the supplier and the plant are located, the formulation considers the uncertainty associated with changes in these conditions. We formulate the robust capacitated international sourcing problem by means of a scenario-optimization approach. When dealing with uncertainty, one of the most common approaches in the literature is to formulate the problem via a set of possible …
Prediction of stock index futures prices based on fuzzy sets and multivariate fuzzy time series
2015
Abstract This paper makes a prediction of Chinese stock index (CSI) future prices using fuzzy sets and multivariate fuzzy time series method. We select Chinese CSI 300 index futures as the research object. The fuzzy time series model combines the fuzzy theory and the time series theory, thus this model can solve the fuzzy data in stock index futures prices. This paper establishes a multivariate model and improves the accuracy of computation. By combing traditional fuzzy time series models and rough set method, we use fuzzy c-mean algorithm to make the data into discrete. Further more, we deal with the rules in mature modules of the rough set and then refine the rules using data mining algor…
Clinical results of transanal endoscopic microsurgery
1988
Using the "transanal endoscopic microsurgery" technique, 140 patients were treated at the Department of Surgery in Cologne and Mainz. Of the patients with adenomas, 68.2% had typical symptoms preoperatively. The postoperative hospital attendance was 8.7 days, with an average resection size of 14.4 cm2. The postoperative complication rate was 5%, and there were no deaths related to the technique. In a prospective controlled trial, 2.2% of the patients with adenomas treated endoscopically in Mainz showed recidivation, requiring reoperation. The follow-up rate was 100%. In 30 cases, microscopic examination revealed carcinoma. Radical reoperation in 8 pT1 tumours showed neither remaining tumour…
Project Method in Adult Education: Self-Experience Analysis
2015
<p><em>The </em><em>project methodhas swiftly gained ground in education and it has nowbecome integral to the education process offering new ways for modernizing the education environment.Implementing projects provides learning opportunities for all of the involved parties – students, teachers, school principals and parents. In this article the Author has analysed the characteristics of the project method and the differences between project-based adult learningand non-adult learning,and the impact ofglobalization on projects. Projects can be implemented not only in the scope of specific subjects or specific schools but also as cooperation projects among schools of di…