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Power Flow Modelling for Power Systems with Dynamic Flow Controller
Roya Ahmadi Ahangar,Abdolreza Sheykholeslami,Hamidreza Ghaffari
Elektrika : Journal of Electrical Engineering , 2008,
Abstract: This paper presents a new method for power flow calculation of power systems in presence of Dynamic Flow Controller (DFC) which is a new member of FACTS controllers. The focus of the paper is to explore how to systematically extend and modify Newton-Raphson power flow method to include DFC. A new steady state model of DFC is introduced for the implementation of the device in the conventional Newton-Raphson power flow. The impact of DFC on power flow is accommodated by adding new entries and modifying some existing ones in the linearised Jacobian equations of the same system without DFC. A case study on a power system located in northern of Iran shows the effectiveness of proposedmethod.
Adsorption of melphalan anticancer drug on the surface of boron nitride cage (B12N12): A comprehensive DFT study
Roya Ahmadi
- , 2020, DOI: 10.26655/JMCHEMSCI.2020.3.1
Abstract: In this study, boron nitride cage (B12N12) adsorption with Melphalan anticancer agent in solvent phase (water) was studied using the density function theory (DFT) method. First, the structure of the Melphalan, B12N12 and their derivatives were geometrically optimized in two different configurations, with a base set of 6-31G* and hybrid B3LYP functions. Then, IR calculations, frontier molecule orbital (FMO) studies, and molecular orbital analysis were performed. In addition, thermodynamic parameters including, Gibbs free energy (ΔGad) and enthalpy (ΔHad) variations indicated that the adsorption of Melphalan with B12N12 is intense, spontaneous, one-way and non-equilibrium. The effect of temperature was studied as well. The results proved that at K 305.15 the highest efficiency was achieved
Adsorption of Tetryl on the Surface of B12N12: A Comprehensive DFT Study
Roya Ahmadi 2
- , 2020, DOI: 10.33945/SAMI/CHEMM.2020.1.4
Abstract: In this study, the adsorption of tetryl on the surface of boron nitride cage was evaluated by density functional theory. For this purpose, the structures of tetryl, B12N12, and the tetryl-B12N12 complexes were geometrically optimized. Then, IR and frontier molecular orbital calculations were performed on them. The calculated adsorption energies, Gibbs free energy changes (ΔGad), adsorption enthalpy changes (ΔHad) and thermodynamic equilibrium constants (Kth) revealed that the adsorption process of both explosives is experimentally feasible, spontaneous, exothermic and non-equilibrium. The specific heat capacity values (CV) showed that the heat sensitivity has been significantly reduced in the tetryl complexes with B12N12. The N-O and C-N bond lengths and the density values demonstrated that tetryl-derived products with boron nitride cage have higher explosive velocity and blasting pressure in comparison to the pure blasting materials without B12N12. The frontier molecular orbital parameters such as band gap, chemical hardness, electrophilicity, chemical potential and charge capacity were also studied and the results proved that boron nitride cage is an ideal electroactive sensing material in order to fabricate novel sensors for the determination of tetryl
Evaluating Adsorption of Proline Amino Acid on the Surface of Fullerene (C60) and Carbon Nanocone by Density Functional Theory
Roya Ahmadi 1
- , 2020, DOI: 10.33945/SAMI/CHEMM.2020.1.6
Abstract: Determination of proline is of great importance and investigating the interaction of this amino acid with nanostructures play a key role in the construction of novel appropriate sensors for proline measurement. In this regard, proline adsorption on the surface of fullerene and carbon nanocone was studied by density functional theory. For this purpose, the structures of fullerene, nanocone, proline and proline-adsorbent complexes at two different configurations were optimized geometrically. Then, IR and Frontier molecular orbital calculations were done in the temperature range of 298.15-398.15 K at 10？ intervals. The obtained adsorption energies, adsorption enthalpy changes, Gibbs free energy variations and thermodynamic equilibrium constants showed that the adsorption of proline on the surface of nanocone is exothermic, spontaneous, one sided and experimentally feasible. In this sense, proline adsorption on the fullerene is endothermic, non-spontaneous, balanced and experimentally impossible. The achieved specific heat capacity values reveal that carbon nanocone can be used in the development of thermal sensors for the determination of proline. The effect of temperature on the adsorption process was also checked out and the results indicate that 298.15 is the optimum temperature for the studied procedure. Some HOMO-LUMO parameters such as energy gap, electrophilicity, maximum charge capacity, chemical hardness and chemical potential were also evaluated. Accordingly, the findings demonstrate that carbon nanocone can be utilized in the electrochemical determination of proline
Adsorption of lomustin anticancer drug on the surface of carbon nanotube: A theoretical study
Roya Ahmadi 2
- , 2020, DOI: 10.33945/SAMI/ECC.2020.5.5
Abstract: The present study aimed to assess the adsorption of Lomustin on the single-walled carbon nanotube which has been examined using Density Functional Theory (DFT), agent in a solvent phase (water) at the B3LYP/6-31G (d) theoretical level. Initially, the structures of Lomustin, carbon nanotube, and Lomustin complexes with carbon nanotubes were designed in Gauss View in three different conformers and were optimized geometrically, on which IR and frontier molecular orbital computations were carried out. Adsorption energy values, Gibbs free energy changes (ΔGad), adsorption enthalpy changes (ΔHad), and equilibrium thermodynamic constants were estimated. The results showed that adsorption process was spontaneous, exothermic and non-equilibrium. The values of specific heat capacity and adsorption enthalpy indicate that this nanostructure can be used to build new thermal sensors to measure Lomustin. The results of molecule orbitals estimations showed that energy gap, after drug absorption on the nanotube surface, decreased significantly and the values of chemical hardness and dipole moment were studied after the interaction of drug with adsorbent and the results showed that drug solubility and reactivity, after adsorption on carbon nanotubes, increased significantly. According to the obtained results for adsorption of Lomustin, this nanostructure can be used as a sensing material in building new electrochemical sensors to measure this drug
Adsorption of TNT on the surface of pristine and N-doped carbon nanocone: A theoretical study
Roya Ahmadi 2
- , 2020, DOI: 10.26655/AJNANOMAT.2020.2.2
Abstract: In this research, the performance of the carbon nanocone as an adsorbent and a sensing material for the removal and detection of trinitrotoluene (TNT) was investigated using the density functional theory. The atomic structures of TNT and its complexes with carbon nanocone were optimized geometrically. Infra-red (IR) and frontier molecular orbital computations were employed to evaluate the interaction of TNT with the carbon nanocone. The obtained negative values of adsorption energies, Gibbs free energy changes, adsorption enthalpy variations and great values of thermodynamic equilibrium constants revealed that the interaction of the TNT with carbon nanocone was exothermic, spontaneous and experimentally feasible. The effect of the nitrogen doping and temperature on the adsorption process was also evaluated and the results indicated that TNT interaction with N-doped carbon nanocone was stronger than that of pristine one. In addition, 298 K was the optimum temperature for the adsorption process. The specific heat capacity values revealed that the heat sensitivity was declined tangibly after the TNT adsorption on the surface of carbon nanocone. Besides, the frontier molecular orbital parameters such as bandgap, electrophilicity, maximum transferred charge proved that the carbon nanocone could be utilized as an excellent sensing material for the construction of new electrochemical sensors for TNT determination. Some structural and energetic features were also discussed in details
Adsorption of 3-picrylamino-1,2,4-triazole on C60 surface as a green fuel: DFT studies
Roya Ahmadi 1
- , 2020, DOI: 10.33945/SAMI/AJGC/2020.2.9
Abstract: In this study, the adsorption of 3-picrylamino-1,2,4-triazole (PATO) On the surface of fullerene (C60) was evaluated by density functional theory using, Becke, three-parameter and Lee-Yang-Parr (B3LYP). PATO as a green fuel, is such a green material and environmental friendly, because after combustion it produces excessive amounts of N2 gas. Due to the importance of these materials in protecting environmental pollution as well as protecting fossil fuel reserves, it is necessary to research in this field. For this purpose, the structures of PATO, C60, and the PATO-C60 complexes were optimized geometrically. Then, IR and Frontier molecular orbital calculations were performed on them. The calculated energies: Gibbs free energy changes (ΔGad) and adsorption enthalpy changes (ΔHad) revealed that the adsorption process of PATO-C60 complexes are experimentally feasible, spontaneous and exothermic. The specific heat capacity values (CV) showed the heat sensitivity has reduced significantly in the PATO-C60 complexes. The N？O and C？N bond lengths and the density values demonstrated that PATO-C60 complexes have higher explosive velocity and blasting pressure in comparison to the pure blasting materials without C60. The Frontier molecular orbital parameters such as band gap, chemical hardness, electrophilicity, chemical potential and charge capacity were also studied
A comprehensive DFT study on the adsorption of tetryl on the surface of graphene
Roya Ahmadi 2
- , 2020, DOI: 10.33945/SAMI/AJGC.2020.3.4
Abstract: In this research study, computational simulation was used to study the adsorption of tetryl on the surface of graphene. For this purpose, the structures of graphene, tetryl and their complexes were optimized geometrically. Then, IR and Frontier molecular orbital calculations were implemented at 298-398 K at the intervals of 10°. The obtained thermodynamic parameters including, Gibbs free energy (ΔGad), adsorption enthalpy alterations (ΔHad), and thermodynamic equilibrium constants (Kth) revealed the adsorption of tetryl is exothermic, spontaneous, non-equilibrium, and experimentally feasible at the both evaluated configurations. The influence of temperature on the thermodynamic factors of the desired process was also evaluated and the results indicated that the 298.15 K was the best temperature for the graphene interaction with tetryl. The calculated specific heat capacity (CV) values revealed that the sensitivity of the produced graphene-tetryl complexes to the heat and shock have declined significantly. The increased nitrogen-oxygen bond lengths after the adsorption of tetryl to the surface of graphene exhibited that the explosive and destructive power of tetryl-graphene derivatives was higher than that of the pure tetryl. Some HOMO-LUMO related parameters such as energy gap, electrophilicity, chemical hardness, maximum transferred charge index (ΔNmax), and chemical potential were also calculated and discussed in details
Why Are Risk-Pooling and Risk-Sharing Arrangements Necessary for Financing Healthcare and Improving Health Outcomes in Low and Lower Middle-Income Countries  [PDF]
Ali Ahangar, Ali Mohammad Ahmadi, Amir Hossein Mozayani Mozayani, Sajjad Faraji Dizaji
Health (Health) , 2018, DOI: 10.4236/health.2018.101010
Abstract: Health is important to economic development, and economic development has an important impact on health outcomes. Health Expenditure makes up a substantial part of the global economy. In the world, the costs of healthcare are increasing; patients are compelled to pay more for treatment, and that makes a lot of people faced to Catastrophic Health Expenditures (CHE) and in long run fall below the poverty line. One of the most urgent and vexing challenges faced by many low- and middle-income countries is how to provide health care for the more than two billion poor people who live in these areas (developing countries). As much as more than 65% (in 2014) of total private health care expenditure in low-income countries comes from out-of-pocket payment by patients. In addition, according to World Bank report (2007), in low and lower middle-income countries was speared nearly 13% of global health spending with 87% the global disease burden. The WHO considers health financing models with high risk pooled, such as health insurance and prepaid schemes, a promising means for achieving universal health-care coverage and promotion health care. A crucial concept in health financing is that of pooling. The WHO defines risk-pooling as the “accumulation and management of revenues in such a way as to ensure that the risk of having to pay for health care is borne by all members of the pool and not by each contributor individually”. The larger degree of pooling, the less people will have to bear the health financial risks. Furthermore, adopting and operating financing policies based on greeter risk pooling/sharing (prepayments) are recommended to all countries (especially in low and lower-middle income countries). It means risk sharing/pooling plays a key role in all financing systems for achieving effectiveness and efficiency health systems.
Dibromido(2,3,5,6-tetra-2-pyridylpyrazine-κ3N2,N1,N6)zinc(II)
Roya Ahmadi,Khadijeh Kalateh,Vahid Amani
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810027820
Abstract: In the title compound, [ZnBr2(C24H16N6)], the ZnII ion is coordinated by the N,N′,N′′-tridentate 2,3,5,6-tetra-2-pyridylpyrazine ligand and two bromide ions, generating a distorted ZnN3Br2 trigonal-bipyramidal geometry for the metal ion, with both bromide ions in equatorial sites. The dihedral angles between the pyrazine ring and the coordinated pyridine rings are 13.3 (2) and 24.8 (2)°; those between the pyrazine ring and the uncoordinated pyradine rings are 31.3 (2) and 44.2 (2)°. In the crystal, inversion dimers linked by pairs of weak C—H...Br hydrogen bonds occur.
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