DFT Study of CO₂ Adsorption on the Zn₁₂O₁₂ Nano-cage

Baei, Mohammad T. Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.12

Covalent functionalization of a $Zn_{12}O_{12}$ nano-cage with $CO_2$ molecule in terms of energetic, geometry, and electronic properties was investigated by density functional theory method. For chemisorption configurations, the adsorption energy of $CO_2$ on the $Zn_{12}O_{12}$ nano-cage for the first $CO_2$ was calculated -1.25 eV with a charge transfer of 1.00|e| from the nano-cage to the $CO_2$ molecule. The results show that $CO_2$ molecule was significantly detected by pristine $Zn_{12}O_{12}$ nano-cage, therefore the nano-cage can be used as $CO_2$ storage. Also, more efficient binding could not be achieved by increasing the $CO_2$ concentration. For Physisorption configurations, HOMO-LUMO gap of the configurations has not changed, while slight changes have been observed in the chemisorption configurations.

A DFT Study on CO₂ Interaction with a BN Nano-Cage

Baei, Mohammad T.,Peyghan, Ali Ahmadi,Bagheri, Zargham Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

Covalent functionalization of a $B_{12}N_{12}$ nano-cage with $CO_2$ molecule has been investigated using density functional theory in terms of energetic, geometric, and electronic property analyses. Results show that besides two physisorption configurations, $CO_2$ preferably tends to perform [2+2] addition on B-N bonds of the cluster which are shared between six-membered and four-membered rings, releasing energy of 14.99 kcal/mol for adsorption of the first $CO_2$ and of 15.45 kcal/mol for the second one (per each molecule). On the basis of calculated density of states, we have found that the electronic properties of the physisorbed $B_{12}N_{12}$ by $CO_2$ have not changed, while slight changes have been predicted in the functionalized cases. Present results might be helpful to provide an effective way to modify the $B_{12}N_{12}$ properties for further purifications and applications.

A New ZVS-PWM Full-Bridge Boost Converter

Baei, Mohammadjavad,Narimani, Mehdi,Moschopoulos, Gerry The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.2

Pulse-width modulated (PWM) full-bridge boost converters are used in applications where the output voltage is considerably higher than the input voltage. Zero-voltage-switching (ZVS) is typically implemented in these converters. A new ZVS-PWM full-bridge converter is proposed in this paper. The proposed converter does not have any of the disadvantages associated with other converters of this type, including a complicated auxiliary circuit, increased current stresses in the main power switches, and load-dependent ZVS operation. The operation of the proposed converter, its steady-state characteristics, and its design are explained and examined. The feasibility of the converter is confirmed with results obtained from an experimental prototype.

Remove of Sulphate Ion from Environmental Systems by using AlN Nanotubes

Baei, Mohammad T.,Hashemian, Saeedeh,Torabi, Parviz,Hosseini, Farzaneh Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.4

The adsorption behavior of the sulphate ($SO{_4}^{2-}$) on the external surface of (5,0), (8,0), and (10,0) zigzag AlNNTs was studied by using density functional calculations. Adsorption energies in the nanotubes are about -8.59, -8.04, -8.60 eV with a charge transfer of 0.59, 0.48, 0.56|e| from the sulphate ion to the nanotubes, respectively. The adsorption energies indicated that sulphate ion can be absorbed strongly on the nanotubes. Therefore, these nanotubes can be used for adsorption of sulphate ion from the environmental systems. It was found that diameter of the AlNNTs has slight role in the adsorption of sulphate ion. The electronic properties of the nanotubes showed notable changes upon the adsorption process.

A New ZVS-PWM Full-Bridge Boost Converter

Mohammadjavad Baei,Mehdi Narimani,Gerry Moschopoulos 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.2

Pulse-width modulated (PWM) full-bridge boost converters are used in applications where the output voltage is considerably higher than the input voltage. Zero-voltage-switching (ZVS) is typically implemented in these converters. A new ZVS?PWM full-bridge converter is proposed in this paper. The proposed converter does not have any of the disadvantages associated with other converters of this type, including a complicated auxiliary circuit, increased current stresses in the main power switches, and load-dependent ZVS operation. The operation of the proposed converter, its steady-state characteristics, and its design are explained and examined. The feasibility of the converter is confirmed with results obtained from an experimental prototype.

Remove of Sulphate Ion from Environmental Systems by using AlN Nanotubes

Mohammad T. Baei,Saeedeh Hashemian,Parviz Torabi,Farzaneh Hosseini 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.4

The adsorption behavior of the sulphate (SO4 2−) on the external surface of (5,0), (8,0), and (10,0) zigzag AlNNTs was studied by using density functional calculations. Adsorption energies in the nanotubes are about −8.59, −8.04, −8.60 eV with a charge transfer of 0.59, 0.48, 0.56|e| from the sulphate ion to the nanotubes, respectively. The adsorption energies indicated that sulphate ion can be absorbed strongly on the nanotubes. Therefore, these nanotubes can be used for adsorption of sulphate ion from the environmental systems. It was found that diameter of the AlNNTs has slight role in the adsorption of sulphate ion. The electronic properties of the nanotubes showed notable changes upon the adsorption process.

DFT Study of CO2 Adsorption on the Zn12O12 Nano-cage

Mohammad T. Baei 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.12

Covalent functionalization of a Zn12O12 nano-cage with CO2 molecule in terms of energetic, geometry, and electronic properties was investigated by density functional theory method. For chemisorption configurations, the adsorption energy of CO2 on the Zn12O12 nano-cage for the first CO2 was calculated −1.25 eV with a charge transfer of 1.00|e| from the nano-cage to the CO2 molecule. The results show that CO2 molecule was significantly detected by pristine Zn12O12 nano-cage, therefore the nano-cage can be used as CO2 storage. Also, more efficient binding could not be achieved by increasing the CO2 concentration. For Physisorption configurations, HOMO–LUMO gap of the configurations has not changed, while slight changes have been observed in the chemisorption configurations.

A DFT Study on CO2 Interaction with a BN Nano-Cage

Mohammad T. Baei,Ali Ahmadi Peyghan,Zargham Bagheri 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

Covalent functionalization of a B12N12 nano-cage with CO2 molecule has been investigated using density functional theory in terms of energetic, geometric, and electronic property analyses. Results show that besides two physisorption configurations, CO2 preferably tends to perform [2+2] addition on B-N bonds of the cluster which are shared between six-membered and four-membered rings, releasing energy of 14.99 kcal/mol for adsorption of the first CO2 and of 15.45 kcal/mol for the second one (per each molecule). On the basis of calculated density of states, we have found that the electronic properties of the physisorbed B12N12 by CO2 have not changed, while slight changes have been predicted in the functionalized cases. Present results might be helpful to provide an effective way to modify the B12N12 properties for further purifications and applications.

Adopting flexibility of the end-plate connections in steel moment frames

M. Ghassemieh,M. Baei,A. Kari,A. Goudarzi,D.F. Laefer 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.5

The majority of connections in moment resisting frames are considered as being fully-rigid. Consequently, the real behavior of the connection, which has some level of flexibility, is ignored. This may result in inaccurate predictions of structural response. This study investigates the influence of flexibility of the extended end-plate connections in the steel moment frames. This is done at two levels. First, the actual micro-behavior of extended end-plate moment connections is explored with respect to joint flexibility. Then, the macro-behavior of frames with end-plate moment connections is investigated using modal, nonlinear static pushover and incremental dynamic analyses. In all models, the P-Delta effects along with material and geometrical nonlinearities were included in the analyses. Results revealed considerable differences between the behavior of the structural frame with connections modeled as fully-rigid versus those when flexibility was incorporated, specifically difference occurred in the natural periods, strength, and maximum inter-story drift angle.

Design of Novel 3D-Scaffold as a Potential Material to Induct Epidermal-Dermal Keratinocytes of Human-Adipose-Derived Stem Cells and Promote Fibroblast Cells Proliferation for Skin Regeneration

Azadeh Izadyari Aghmiuni,Mazyar Sharifzadeh Baei,Saeed Heidari Keshel,Azim Akbarzadeh Khiyavi 한국섬유공학회 2020 Fibers and polymers Vol.21 No.1

Dermal lesions and chronic wounds associated with burns or some diseases like diabetes are the more importantpublic health concerns which can affect the quality of life. Currently, tissue engineering is considered as the most effectivetherapeutic method although the design of polymeric substrates for epidermal-dermal differentiation and wound healing(scar-free) is the main challenge. For this purpose, we designed a hybrid three-dimensional scaffold (CPCP) based oncollagen/chitosan modified by PEG/PCL composite that can imitate differentiation pattern of both epidermis/dermis cells, viamimicking the structure and function of human skin. The physicochemical, mechanical and biological properties of designedscaffolds were evaluated to study their function for skin tissue engineering applications. Comparison of FTIR analysisshowed a chemical similarity between CPCP and decellularized dermal matrix (DDM). Our results showed that combinationof two natural/two synthetic polymers led to the formation of stronger 3D-network together with higher modulus (~18), waterabsorption (4-fold), porosity (~92) and consequently lower pores size (~54 μm), compared to natural, synthetic and natural/synthetic copolymer-based scaffolds. The observation of human skin fibroblast cells proliferation and morphology showedthat CPCP was more beneficial to cell adhesion, proliferation, and extension than that of other designed scaffolds due to itshydrophilicity and higher wettability (WCA=60 o). According to the results of RT-PCR, the more expression of epidermaldermalkeratinocytes induced by human-adipose-derived stem cells was observed on the CPCP along with a pattern similar toskin. The results demonstrate CPCP can act as a super-absorbent substrate/dressing for continuous absorption of woundexudates. Furthermore, it can potentially be effective for re-epithelialization of skin together with its derivative (hair follicles,sebaceous/sweat glands). This study indicates new insights into the design of skin- engineered scaffolds.