Effect of calcination and reaction conditions on the catalytic performance of Co–Ni/Al2O3 catalyst for CO hydrogenation

Akbar Zare,Mehdi Shiva,Ahad Zare,Ali Akbar Mirzaei 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.6

The Co–Ni/Al2O3 catalysts prepared using impregnation procedure, were used for the Fischer–Tropsch synthesis. The effect of calcination conditions of the catalyst as well as reactor situation was studied. It was found that the catalyst calcined at 550 8C for 6 h in air atmosphere has shown the best catalytic performance for CO hydrogenation. The best operational conditions were obtained as following:T = 350 8C, P = 1 atm and H2/CO = 2/1.

A brief review on graphene applications in rechargeable lithium ion battery electrode materials

Sameen Akbar,Muhammad Rehan,Liu Haiyang,Iqra Rafique,Hurria Akbar 한국탄소학회 2018 Carbon Letters Vol.28 No.-

Graphene is a single atomic layer of carbon atoms, and has exceptional electrical, mechanical, and optical characteristics. It has been broadly utilized in the fields of material science, physics, chemistry, device fabrication, information, and biology. In this review paper, we briefly investigate the ideas, structure, characteristics, and fabrication techniques for graphene applications in lithium ion batteries (LIBs). In LIBs, a constant three-dimensional (3D) conductive system can adequately enhance the transportation of electrons and ions of the electrode material. The use of 3D graphene and graphene-expansion electrode materials can significantly upgrade LIBs characteristics to give higher electric conductivity, greater capacity, and good stability. This review demonstrates several recent advances in graphenecontaining LIB electrode materials, and addresses probable trends into the future.

Numerical study of different conduction models for Al2O3-water nanofluid with variable properties inside a trapezoidal enclosure

Ali Akbar Abbasian Arani,Ali Akbar Azemati,Mohammad Rezaee,Behzad Shirkavand Hadavand 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.5

Natural convection in enclosures containing nanofluids is important in physical and environmental applications. Different models for conduction have been developed because of the importance of this phenomenon in natural convection in enclosures. In this study, effects of conduction models of Chon, Corcione, Khanafer, and Koo and Kleinstreuer on the natural convection inside a trapezoidal enclosure with hot and cold walls are evaluated numerically. The enclosure contains Al 2 O 3 -water nanofluid with variable properties. Effects of the conduction models on fluid flow, natural convection, variations in volume fraction, and diameter of nanoparticles in the models, as well as the variations in the Rayleigh number, are examined. Results show that at Rayleigh numbers of 10 5 and 10 6 , the maximum and minimum values of the average Nusselt number are obtained using the models of Khanafer and Chon, respectively. In all models, the average Nusselt number presents upward and downward trends when the volume fraction of nanoparticles increases but decreases when the diameter of the nanoparticles increases. At Ra = 10 5 in all models, as the volume fraction of nanoparticles increases, the nanofluid provides a higher average Nusselt number compared with the base fluid. By contrast, at Ra = 10 6 , at volume fractions larger than 0.01 and using the model of Chon, the average Nusselt number of the nanofluid is lower compared with that of the base fluid.

A Product Inhibition Study on Adenosine Deaminase by Spectroscopy and Calorimetry

(Ali Akbar Saboury),(Ghasem Ataie Jafari),(Ali Akbar Moosavi Movahedi),(Mohammad Reza Housaindokht),(Gholam Hosain Hakimelahi),(Adeleh Divsalar) 생화학분자생물학회 2002 BMB Reports Vol.35 No.3

Kinetic and thermodynamic studies have been made on the effect of the inosine product on the activity of adenosine deaminase in a 50 mM sodium phosphate buffer, pH 7.5, at 27oC using UV spectrophotometry and isothermal titration calorimetry (ITC). A competitive inhibition was observed for inosine as a product of the enzymatic reaction. A graphical-fitting method was used for determination of the binding constant and enthalpy of inhibitor binding by using isothermal titration microcalorimetry data. The dissociation-binding constant is equal to 140 μM by the microcalorimetry method, which agrees well with the value of 143 μM for the inhibition constant that was obtained from the spectroscopy method.

A Product Inhibition Study on Adenosine Deaminase by Spectroscopy and Calorimetry

Saboury, Ali Akbar,Divsalar, Adeleh,Jafari, Ghasem Ataie,Moosavi-Movahedi, Ali Akbar,Housaindokht, Mohammad Reza,Hakimelahi, Hosain 생화학분자생물학회 2002 Journal of biochemistry and molecular biology Vol.35 No.3

Kinetic and thermodynamic studies have been made on the effect of the inosine product on the activity of adenosine deaminase in a 50 mM sodium phosphate buffer, pH 7.5, at $27^{\circ}C$ using UV spectrophotometry and isothermal titration calorimetry (ITC). A competitive inhibition was observed for inosine as a product of the enzymatic reaction. A graphical-fitting method was used for determination of the binding constant and enthalpy of inhibitor binding by using isothermal titration microcalorimetry data. The dissociation-binding constant is equal to $140\;{\mu}M$ by the microcalorimetry method, which agrees well with the value of $143\;{\mu}M$ for the inhibition constant that was obtained from the spectroscopy method.

The electroless plating of Cu-Ni-P alloy onto cotton fabrics

Akbar Khodaparast Haghi,Arezoo Afzali,Vahid Mottaghitalab,Mahmood Saberi Motlagh 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.4

The objective of this study is to apply the electroless plating of Cu-Ni-P alloy on cotton fabrics to the preparation of conductive fabrics. The alloy composed of infinit small amount of nickel and phosphorus particle originated from sodium hypophosphite and nickel sulphate respectively as reducing agent and hypophosphite oxidation accelerator. Electroless plating of Cu-Ni-P alloy on cotton fabrics and effect of plating on the physical and mechanical properties of alloy coated fabrics as well as electromagnetic interference (EMI) shielding effectiveness were reported in detail. In this research highly washing and abrasion durable conductive fabrics obtained with supreme shielding effectiveness.

The Use of Bootstrap for Weight Control in Data Envelopment Analysis

Akbar Amiri,Saber Saati,Alireza Amirteimoori 대한산업공학회 2018 Industrial Engineeering & Management Systems Vol.17 No.4

Data Envelopment Analysis includes a wide range of mathematical models and is used for assessing the relative efficiencyof a set of homogenous Decision Making Units (DMUs). Multiplicative DEA models achieve a set of weightsfor input and output variables for each DMU. Based on these weights, relative efficiency of each DMU is evaluated. Determining different weights for same factor in a set of homogenous DMUs is not realistic. To solve this problem,Common Set of Weights (CSW) is used. To improve the results of DEA models and reduce the weight flexibility,bootstrap method is used to determine a CSW. The aim of this article is to determine the CSW by finding a confidenceinterval for weights with bootstrap. By evaluating these intervals, a Probabilistic Common Set of Weights (PCSW) isobtained, which provides flexibility for weights.

A numerical study on drying of porous media

Akbar Khodaparast Haghi,Nima Amanifard 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.2

In this study, two-dimensional conjugate heat and mass transfer in porous body and drying air during the drying process were numerically investigated by finite volume (FV) method, which guarantees the conservation of mass, momentum and the energy during the numerical solution. The full NS-equations (including buoyancy terms), energy equation and concentration equation are considered for external flow and for porous field coupled energy and moisture transfer equations are used. The numerically captured curve shows the same behavior of the drying process. Drying flow velocity shows proportional effect on moisture removal rate with a factor between 1/4 and 1/5 in Reynolds range of 50 to 1,000. Also, buoyancy forces have an effect on flow streamlines, the distribution of vapor concentration, moisture profile, and considerably increase drying rate. This increment was investigated in Reynolds number range of 50 to 1,000, and its minimum value was found in a Reynolds number of 1,000, which was about 15 percent.

FTO-free counter electrodes for dye-sensitized solar cells using carbon nanosheets synthesised from a polymeric carbon source

Akbar, Zico Alaia,Lee, Jae-Seon,Kang, Jinhyeon,Joh, Han-Ik,Lee, Sungho,Jang, Sung-Yeon The Royal Society of Chemistry 2014 Physical chemistry chemical physics Vol.16 No.33

<P>Highly conductive carbon nanosheets (CNSs) are fabricated using a polymeric carbon source and subsequently applied as the counter electrodes (CNS-CEs) for dye-sensitized solar cells (DSSCs). The CNSs have a similar structure to multilayered graphene, and their high electrical conductivity and electrocatalytic activity enable them to have a dual-function as both CEs and charge supporting electrodes. CNSs form a unique CE material that functions successfully while being metal- and fluorine doped tin oxide (FTO)-free and allowing DSSCs to achieve ∼5% power conversion efficiency. The chemical structure, electrical properties, electrocatalytic activity, and work function of the CNS-CEs prepared under various conditions of carbonization are investigated, and their effects on the performance of the corresponding DSSCs are discussed. Carbonization temperature is shown to have influenced the size of graphitic domains and the presence of heteroatoms and functional groups in CNS-CEs. The change in the graphitic domain size has a marginal influence on the work function of the CNS-CEs and the overpotential for the reduction of the redox couples (I<SUP>−</SUP>/I<SUB>3</SUB><SUP>−</SUP>). However, the electrical conductivity of CNS-CEs and the charge transfer resistance at CE/electrolyte interfaces in the DSSCs are considerably influenced by the carbonization condition. Our study shows that CNSs serve as efficient, FTO-free CE materials for DSSCs, and they are appropriate materials with which the effects of the chemical/physical properties of graphene-based materials on the electrode performance of various electrochemical devices may be studied.</P> <P>Graphic Abstract</P><P>Dye-sensitized solar cells were fabricated using novel carbon nanosheets synthesized from polymeric sources as the Pt and FTO-free counter electrodes. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cp01913j'> </P>

Self-cleaning Properties of TiO2-SiO2-In2O3 Nanocomposite Thin Film

Akbar Eshaghi,Ameneh Eshaghi 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.11

TiO_2 -SiO_2 -In_2O_3 nanocomposite thin film was deposited on the glass substrates using a dip coating technique. The morphology, surface composition, surface hydroxyl groups, photocatalytic activity and hydrophilic properties of the thin film were investigated by AFM, XPS, methyl orange decoloring rate and water contact angle measurements. The hydroxyl content for TiO_2, TiO_2-SiO_2 and TiO_2-SiO_2-In_2O_3 nanocomposite films was calculated to be 11.6, 17.1 and 20.7%, respectively. TiO_2-SiO_2-In_2O_3 film turned superhydrophilic after 180-min irradiation with respect to pure TiO_2 and TiO_2-SiO_2 thin films. The photocatalytic decomposition of methyl orange for TiO_2, TiO_2-SiO_2 and TiO2-SiO_2-In_2O_3 thin films was measured as 38.19, 58.71 and 68.02%,respectively. The results indicated that SiO2 and In2O3 had a significant effect on the hydrophilic, photocatalytic and self-cleaning properties of TiO_2 thin film.