309 research outputs found
Modeling and Solving Project Portfolio and Contractor Selection Problem Based on Project Scheduling under Uncertainty
AbstractIn this paper a new formulation of the project portfolio selection problem based on the project schedules in uncertain circumstances have been proposed. The project portfolio selection models usually disregard the project scheduling, whereas is an element of the project selection process. We investigate a project portfolio selection problem based on the schedule of the projects, so that the minimum expected profit would be met in the shortest possible time period. Also due to uncertain nature of durations of the activities, this duration considered as the semi-trapezoidal fuzzy numbers. Finally, a fuzzy linear programming model is developed for the problem, where the results indicated the validity of the presented model
A REVIEW OF CONTRASTIVE ANALYSIS HYPOTHESIS WITH A PHONOLOGICAL AND SYNTACTICAL VIEW: A CROSS-LINGUISTIC STUDY
Although contrastive analysis has often been questioned for its inadequacy to predict the transfer errors that learners will make in actual learning contexts it cannot be easily denied that “such interference does exist and can explain difficulties” (Brown, 1994, p. 200), especially in the phonological aspects of second/foreign language learning. In this line, the present research is trying to shed light on the concept of contrastive analysis hypothesis by focusing on the background and origins of the concept, then the procedures and its different versions. Also, the current study will discuss the differences and similarities exist in the phonology and syntax of two languages, namely Persian and English in order to be able to find the areas of possible difficulty for L2 learners of English
Investigation of the electrochemical behavior of curcumin in a mixed solution of water and ethanol by means of cyclic voltammetry and quantum chemical calculations
In the present work, a computational analysis of the chemical structure of curcumin, the most important component of turmeric, is carried out by means of state-of-the-art methods of calculations. High-level ab initio calculations (G4) along with reliable methods of density functional theory (DFT) have been used to studythe enol-diketo tautomerism of curcumin. The electrochemical behavior of curcumin has been also investigated by means of cyclic voltammetry and standard theoretical quantum chemical calculations in a mixed solvent of water-ethanol. The pH dependence of the redox activity of curcumin derivatives in the mixture solutions at different temperatures has been used for the experimental determination of the standard reduction potential and changes of entropy, enthalpy, and Gibbs free energy for the studied reaction. The electrooxidation process leads to several products that are studied theoretically using DFT calculations. The calculated values of E° are in good agreement with the experiment. Uniquely, the change of solvation energy for the studied reaction has been investigated by two models and the results are in perfect agreement with one another
Synthesis, X-ray structural characterization, and DFT calculations of binuclear mixed-ligand copper(II) complexes containing diamine, acetate and methacrylate ligands
The dinuclear Cu(II) complexes [Cu(en)(MAA)(µ-CH3COO)]2 (1) and [Cu(pn)(MAA)(µ-CH3COO)]2 (2) where MAA, en and pn are methacrylate, ethylendiamine and 1,3-propylendiamine, respectively, have been synthesized and characterized by elemental analysis, FT-IR and UV-Vis spectroscopy. The structures of the complexes have been determined by single-crystal X-ray diffraction analyses. In the dinuclear complexes 1 and 2 the two copper centers are five-coordinated and exhibit distorted square pyramidal geometries. The theoretical geometries of the studied compounds have been calculated by means of density functional theory (DFT) at the B3LYP/6-311+G(d,p)/LanL2DZ level considering effective core potential (ECP)
Operational Risk Management (ORM) 1
Abstract: This article discusses the management process of operational risk in financial institutions. While risk management has always been an integral part of financial activity, the 1990s has seen risk management establish itself as a key function within banks and other financial institutions. With greater emphasis on ensuring that money is not lost through adverse market conditions, counterparty failure or inappropriate controls, systems or people, risk management has become a discipline in its own right within financial markets. In this paper, we first review the different steps of the risk management process with respect to operational risk in the banking industry: the definition of operational risk, quantitative and qualitative methods for measuring operational risk, and risk management methods with respect to operational risk. In this study, we focus on the particular difficulties that arise with operational risk and argue that these steps cannot be treated separately as opposed to the management process of market or credit risk
Synthesis, X-ray Structural Characterization, and DFT Calculations of Mononuclear Nickel(II) Complexes Containing Diamine and Methacrylate Ligands
The mononuclear Ni(II) complexes [Ni(en)2(H2O)2](MAA)2 (1) and [Ni(pn)2(MAA)2] (2), where MAA, en and pn are
methacrylate, ethylendiamine and 1,3-propylendiamine, respectively, have been synthesized and characterized by elemental
analysis, FT-IR and UV–Vis spectroskopy. Structures of the complexes have been determined by single-crystal
X-ray diffraction analyses. In the nickel(II) complexes 1 and 2 nickel(II) ion is six-coordinate and has a distorted octahedral
geometry. Ni(II) is bonded to four nitrogen atoms of the two diamines and additionally to two oxygen atoms of aqua
ligand in 1, and two oxygen atoms of methacrylate ligands in 2. The theoretical geometries of the studied compounds
have been calculated by means of density functional theory (DFT) at the B3LYP/6-311+G(d,p)/LanL2DZ level and considering
effective core potential (ECP). The comparison of the results indicates that the employed DFT method yields
good agreement with experimental data
Classical generalized constant coupling model for geometrically frustrated antiferromagnets
A generalized constant coupling approximation for classical geometrically
frustrated antiferromagnets is presented. Starting from a frustrated unit we
introduce the interactions with the surrounding units in terms of an internal
effective field which is fixed by a self consistency condition. Results for the
magnetic susceptibility and specific heat are compared with Monte Carlo data
for the classical Heisenberg model for the pyrochlore and kagome lattices. The
predictions for the susceptibility are found to be essentially exact, and the
corresponding predictions for the specific heat are found to be in very good
agreement with the Monte Carlo results.Comment: 4 pages, 3 figures, 2 columns. Discussion about the zero T value of
the pyrochlore specific heat correcte
Harnessing entropy to direct the bonding/debonding of polymer systems based on reversible chemistry
The widely accepted approach for controlling polymer debonding/rebonding properties in responsive materials has been to purposefully engineer the functional end-groups responsible for monomer dynamic bonding. Here, however, we evidence that the debondin
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