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162 results on '"Najafi, Mojtaba"'

9. Simultaneously planning of transmission line expansion and energy storage in order to maximize the capacity of wind farms.

Author

Nazeri, Milad, Najafi, Mojtaba, Hosseinpour, Majid, and Simab, Mohsen

Subjects
*GRID energy storage, *POWER resources, *ENERGY storage, *ELECTRIC lines, *RENEWABLE natural resources, *WIND power plants
Abstract

The speed of using renewable resources is expanding day by day. Renewable energy systems have many benefits for energy supply that do not include diesel, natural gas, or coal. Despite the many advantages, the use of renewable resources also includes basic challenges. With the presence of these sources, many technical issues must be considered in the network, the most important of which are voltage quality and network losses. The presence of these power plants can reduce fossil fuel costs and help reduce emissions. However, the high‐capacity connection of these types of power plants in the transmission networks despite the uncertainty may cause the congestion of transmission lines, increase losses and decrease voltage quality. Therefore, to reduce the need to build transmission lines, energy storage devices can be installed and energy can be stored and returned to the network in certain hours. The purpose of this paper is to build the maximum capacity of wind power plants in the transmission network in such a way that its profitability is guaranteed. For this purpose, in addition to considering the costs related to the power plant, the costs of storage devices and the construction of possible new lines have been considered. Also, improving the technical conditions of the network and reducing the maximum emission after installing these units is considered as a multiobjective function. The problem tested on the standard IEEE test transmission network and the results show that it is possible to determine the maximum profitable capacity of wind power plants. [ABSTRACT FROM AUTHOR]

Published
2024
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13. Frequency‐Constrained Expansion Planning in Competitive Market considering Renewable Failures.

Author

Gorjipour, Hamid, Najafi, Mojtaba, Moaddabi Pirkolahchahi, Naghi, and Bureerat, Sujin

Subjects
*MARGINAL pricing, *ROBUST optimization, *ENVIRONMENTAL economics, *POLLUTION, *RENEWABLE energy sources
Abstract

In modern generation expansion planning of power systems, installing grid‐connected renewable energy systems is preferred than thermal units due to their low generation cost and environmental pollution. However, the expanded power system must have ability to resist against any outages influenced on the frequency response of the system. So, several frequency‐constrained expansion planning models are extracted to provide a reliable infrastructure to manage the frequency behavior. The main distinction of our model with others is considering the failure of grid‐connected renewables in the expansion planning models. Furthermore, due to the lack of information about the uncertainty of malfunctions, a distributionally robust optimization approach is applied to the problem under several ambiguity radiuses. The results of implementing the proposed method on the IEEE RTS96 case show that increasing the penetration of malfunctioned units can lead to more investment on the thermal units to prevent frequency violation under any outage in the system. With increase of the Kullback–Leibler divergence from zero (stochastic) to 3 (robust), the cost of the robust model is increased about 0.02%. The model is designed for the deregulated market to increase the competition of market through maximizing their benefit and line congestion management with local marginal pricing techniques. [ABSTRACT FROM AUTHOR]

Published
2024
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26. INVESTIGATION OF THE EFFECTS OF THE REINFORCEMENT OF CIVIL SOCIETY AND ADMINISTRATIVE AMENDMENTS ON GOOD GOVERNANCE AS WELL AS THE REDUCTION OF ADMINISTRATIVE CORRUPTION (THE CASE OF THE TAX OFFICE OF THE CITY OF ARAK)/INVESTIGACAO DOS EFEITOS DO REFORCO DA SOCIEDADE CIVIL E DAS ALTERACOES ADMINISTRATIVAS APLICAVEIS A BOA GOVERNANCA, BEM COMO A REDUCAO DA CORRUPCAO ADMINISTRATIVA (O CASO DA SECRETARIA FISCAL DA CIDADE DE ARAK)

Author

Goudarzi, Farhad, Najafi, Mojtaba, and Eslambulchi, Alireza

Published
2018

28. Analysis and Identification of Putative Novel Peptides Purified from Iranian Endemic Echis Carinatus Sochureki Snake Venom by MALDI-TOF Mass Spectrometry.

Author

Nasrabadi, Nafiseh Nasri, Vatanpour, Hossein, Dounighi, Nasser Mohammadpour, Najafi, Mojtaba, Ahmadinejad, Minoo, Bayatzadeh, Mohammad Ali, and pouyanmehr, Giti

Subjects
SNAKE venom, PEPTIDE mass fingerprinting, MASS spectrometry, BLOOD platelet aggregation, TIME-of-flight mass spectrometry, PEPTIDES
Abstract

The Iranian Echis Carinatus (IEC) venom is an exclusive natural source of bio-substances for a wide range of purposes in the blood coagulation cascade. The present study for the first time was aimed to assess novel pro-coagulant, anti-coagulant and anti-platelet proteins, named EC1.5 (a), EC5.1 (b) and EC4 (a) from Iranian Echis Carinatus (IEC) venom.These peptides were purified by multi-step chromatography methods. Hematological properties were measured using activated clotting tests, platelet aggregation studies, and hemorrhage assessment. Subsequently, these proteins were identified through both their intact molecular mass and peptide mass fingerprint (PMF) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Multiple sequence alignments were performed by ClustalW, Bioedit software. Molegro Data Modeller (MDM) 3.0 software was used to predict the putative tertiary structure of proteins.EC1.5 (a), a single-band protein with a molecular mass of 66 and 55 kDa, was observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a reduced and non-reduced state, respectively. Based on the Mascot results, we considered that EC1.5 (a) is a metalloproteinase of group II which exhibited potent pro-coagulant activity. It is predicted that the EC1.5 (a) with hemorrhagic activity, potentially is a metalloproteinase/disintegrin region that constitutes the disintegrin-like domains. Our findings demonstrate that the disintegrin domain of EC1.5 (a) lacks platelet aggregation inhibitory activity. On the contrary, this factor shows the property of a platelet aggregation inducer. Also, the EC5.1 (b) was observed as a single-band protein with a molecular mass of 7.5 kDa. EC5.1 (b) showed both anti-coagulant and anti-platelet properties. Additionally, the structure of the EC5.1 (b) fraction is expected to be similar to that of phospholipase A2, while EC4 (a) structure is potentially very similar to that of Echistatin with 5 kDa molecular mass. We introduce the predicted structure of P-II snake venom metalloproteinase/ disintegrin domains, phospholipase A2 and Echistatin-like fractions. Further research is therefore needed to determine the complete structure of these novel fractions and elucidate their mechanism of action and future therapeutic applications of cardiovascular and homeostasis disorders. [ABSTRACT FROM AUTHOR]

Published
2023
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30. The evaluation of Isolated KH1-29 properties for producing α-amylase from a novel native highly thermostable, thermophilic and alkaline Bacillus sp

Author

Danesh, Vahid, Ozcan, Numan, and Najafi, Mojtaba

Subjects
Isolation, Bacillus sp., Thermophile, Alkaline, α-Amylase, Molecular weight
Abstract

Alkaliphilic and thermophilic bacillus sp. KH1-29 which was isolated from Caspian Lake of Iran, produced thermostable α-Amylase at 55°C, pH 8.0. The molecular weight of the enzyme was estimated 45 kilodallton using sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The enzyme showed working pH range of 7-8 with an optimum pH of 8.0. The temperature optimum of the enzyme was found at 90°C. α-Amylase production by Thermophilic bacillus sp. strain reached to maximum quantity at 36h after cultivation analyzed according to the Lowry method. According to Lowry method with levels of 0.63 mmol protein/min, the a-amylase production in the mentioned strain reached to maximum levels at 36 h after cultivation with levels of 0.63 mmol protein/min. As a result, according to information obtained by the enzyme it is qualified for use in biotechnological applications and all its properties make it a useful tool for bio-bleaching in pulp and paper industry. Key words: Isolation, Bacillus sp., Thermophile, Alkaline, α-Amylase, Molecular weight REFERENCES Alghabpoor, S.S., Panosyan, H. and Popov, Y. (2013). Purification and characterization of a novel thermostable and acid stable α-amylase from Bacillus Sp. Iranian S1. Int J Eng 26(8): 815-820. Al-Quadan, F., Akel. H. and Natshi, R. (2009). Characteristics of a novel highly thermostable and extremely thermophilic alkalitolerant amylase from hyperthermophilic Bacillus strain HUTBS51. OnLine J Biol Sci 9(3): 67- 74. Amal A. Hassan, Esam H. Mansour, Abo El-Fath A. El Bedawey and Mohamed S. Zaki (2015). Effect of α-amylase enzyme on rheological properties and quality of betifore-type cookies. Biolife 2015; 3(1); 31-39. Arikan, B., Unaldi, N., Coral, G., Colak, O., Aygan, A. and Gulnaz, O. (2003). Enzymatic properties of a novel thermostable, thermophilic, alkaline and chelator resistant amylase from an alkaliphilic Bacillus sp. isolate ANT- 6. Process Biochem 38: 1397-1403. 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Purification and enzymatic identification of an acid stable and thermostable α-amylase from Rhizopus microspores. J Inst Brew 118(3): 309-314.. Uzyol KS, SarıyarAkbulut B, Denizci AA, Kazan D et al. (2012). Thermostable α-amylase from moderately halophilicHalomonas sp. AAD21. Turk J Biol 36: 327-338.

Published
2022
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