A facile synthesis of CdS nanoparticles using EDTA and EG as capping agent

A facile synthesis of CdS nanoparticles using EDTA and EG as capping agent

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Part of #A facile synthesis of CdS nanoparticles using EDTA and EG as capping agent# :

Publishing year : 2013

Conference : Second National Conference on Nanotechnology from theory to application

Number of pages : 9

Abstract: II-VI semiconductor nanoparticles are presently of great interest for their applications in optoelectronics and photonics. In the present study, our goal was to find easy and reproducible methods for producing CdS nanoparticles. In the present study, we propose the preparation of CdS nanoparticles at 90 C by co-precipitation method and two different capping agents, ehtylene glycol (EG) and ethylenediamine tetraacetic acid (EDTA). The CdS nanoparticles obtained were characterized by XRD, SEM and UV-vis spectra. The XRD analysis shows that the prepared samples are in a hexagonal phase. The broad spectrum of the XRD pattern indicates the nanocrystalline behavior of the particles. The average nanocrystallite sizes calculated from the Debye-Scherrer formula were found to be 9.2 nm and 16.5 nm for EDTA capped CdS and EG capped CdS nanoparticles, and the absorption peak appears at about 309.2 and 463 nm, which is quite a blue shift from absorption Edge of the bulk. The morphology of the CdS nanoparticles was studied by SEM. The observed spherical morphology is the same for samples. EDTA-capped CdS nanoparticles had a smaller particle size and showed better dispersity than EG-capped CdS.

Kinetic modeling of bioleaching process of iron removal from Kaolin

Kinetic modeling of bioleaching process of iron removal from Kaolin

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Part of #Kinetic modeling of bioleaching process of iron removal from Kaolin# :

Publishing year : 2009

Conference : Sixth International Congress of Chemical Engineering

Number of pages : 6

Abstract: In this study, we developed a kinetic model to evaluate its fitness for batch cultivation of Aspergillus niger for the bioleaching process of iron removal from kaolin. A simple model was proposed using the logistic equation for growth, and the Luedeking-Piret equations for iron removal, acid formation and sucrose consumption. We compared the performance of our model against that obtained by empirically experimental data. The model appeared to provide a reasonable description of each parameter during the growth phase. The experimental results also suggest that iron removal from kaolin was somewhat associated with growth-related, but with increasing iron concentration in the solution, cell growth was limited.

Analysis of Quantum Cascade Laser Using A Large-Signal Circuit Model

Analysis of Quantum Cascade Laser Using A Large-Signal Circuit Model

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Part of #Analysis of Quantum Cascade Laser Using A Large-Signal Circuit Model# :

Publishing year : 2013

Conference : 5th National Conference on Electrical and Electronic Engineering of Iran

Number of pages : 4

Abstract: In this work, a circuit model of quantum cascade lasers (QCLs) is based on three-level level equations, considering the unipolar behavior of electrons in quantum wells. This model can predict the dependence of laser characteristics on the affecting parameters. The dynamic responses of QCL are analyzed using a presented model using the HSPICE simulator. Simulation results reveal that short photon lifetimes in optical cavity yield extended modulation bandwidths but reduced optical output power levels of QCL devices.

Improving the Forming Pressure Curves in Tube Hydroforming Process for AA1050 Alloy at Various Temperatures

Improving the Forming Pressure Curves in Tube Hydroforming Process for AA1050 Alloy at Various Temperatures

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Part of #Improving the Forming Pressure Curves in Tube Hydroforming Process for AA1050 Alloy at Various Temperatures# :

Publishing year : 2012

Conference : Second International Aluminum Conference

Number of pages : 5

Abstract: Reduction of weight and increase of corrosion resistance are among the most advantageous applications of Aluminum alloys in the automotive industry. Low formationability at room temperature is a major problem in the application of these alloys. This problem is due to their microstructure (hexagonal closed pack in magnesium alloys and alloy elements in aluminum alloys), which limits the number of slip planes at room temperature. Forming at high temperature can solve this problem. In this paper, the warm hydroforming of AA1050 aluminum tubes has been studied numerically. A warm tube hydroforming was designed and fabricated. Aluminum tubes were formed at high temperatures. Simulation of the process is performed using MSC. Mac commercial software and thickness distribution were studied at various temperatures. Results showed that increasing temperature improved thickness distribution. The pressure curves that were obtained using available equations for forming at room temperature have been improved to reduce thinning in the final part. Simulations were performed in two states, which are called constrained bulge and free bulge. To produce a part without wrinkling and also to obtain minimal thinning, an axial feeding curve is suggested.

Implementation of Urban Regeneration Approach with Focus on Social Capital Benefits (Case Study: Sangelaj Neighborhood)

Implementation of Urban Regeneration Approach with Focus on Social Capital Benefits (Case Study: Sangelaj Neighborhood)

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Part of #Implementation of Urban Regeneration Approach with Focus on Social Capital Benefits (Case Study: Sangelaj Neighborhood)# :

Publishing year : 2014

Conference : The First International Congress of New Horizons in Architecture and Urbanism

Number of pages : 13

Abstract: In this article, we are practicing the regeneration of the Sangelaj neighborhood as one of Tehran's oldest neighborhoods, located close to the Bazar and Golestan Royal Palace, and had a critical role in the city's social and spatial relationships. Our goal is to improve the quality of urban life and create conditions for more social interactions among the residents. At first, some principles and definitions in the field of historical and down town areas renewal and rehabilitation are given. Then we talk about Urban Regeneration approach and social capital and its functions in the society. Trends of transformation and decline in the inner city are reviewed and some guidelines are given to reverse the social, economic and physical decline and fading in the historic city. Subsequently, social and economic, cultural and physical studies are implemented and analyzed to figure out the neighborhood Today's characteristics and conditions and its situation in the old city of Tehran. Finally, after these analyzes and reaching a primary vision, strategic and policy plans are presented for improving the neighborhood in the urban design framework. The intervention area is a street in the neighborhood known as Gozare Moayer in the historic Tehran maps. In this area of the neighborhood, containing some of the main functions and uses, we propose some action plans, namely green spaces and cultural and social centers, and some measures are taken to improve the security and safety and appearances of the neighborhood.

Abbreviation in the Net Communication

Abbreviation in the Net Communication

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Part of #Abbreviation in the Net Communication# :

Publishing year : 2013

Conference : First National Conference on English Language, Literature and Translating

Number of pages : 13

Abstract: The present study is devoted to the use of the abbreviation in the net communication. Abbreviation is a short way of writing a word or phrase that can also be written out in full. The first section of this paper focuses on the impossibility for one to use the Internet service, unless that one is competent in English, while the second one is to present the acronomy term as a kind of linguistic abbreviation which should not be pronounced as Series of letters but as a word (Enarsson, 2006: 3). The second section itself is subdivided into three subsections, the first of which is to manifest acronomy as a form of jargon through which the communicator's cultural identity can be identified. The second is to show how such a linguistic variety may be useful to save the effort and time for the originator and the communication receiver. The third subsection introduces acronomy as a register; A variety of languages that are resorted to in a particular situation. It is a distinctive medium of the net communication. Finally, the conclusion is to summarize the findings of the study

SYNTHESIS AND CHARACTERIZATION OF TWO NEW CADMIUM COMPLEXES OF PYRIDINE-2,5-DICARBOXYLIC ACID N-OXIDE

SYNTHESIS AND CHARACTERIZATION OF TWO NEW CADMIUM COMPLEXES OF PYRIDINE-2,5-DICARBOXYLIC ACID N-OXIDE

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Part of #SYNTHESIS AND CHARACTERIZATION OF TWO NEW CADMIUM COMPLEXES OF PYRIDINE-2,5-DICARBOXYLIC ACID N-OXIDE# :

Publishing year : 2016

Conference : Third National Conference on New Technologies in Chemistry, Petrochemicals and Nano Iran

Number of pages : 9

Abstract: Due to their various applications, we decided to oxygenate the piridine ring of pyridine-2,5-dicarboxylic acid as a N-oxide to study the synthesis, coordination modes and Structure of these compounds in view of crystal engineering concepts. In this work, we report the synthesis of two new coordination complexes based on the pyridine-2,5-dicarboxylic acid N-oxide (2,5-H2pydco) as a ligand with a CdII metal ion in the presence of heterocyclic amines such as 1, 10-phenanthroline (phen) and 2,2-bipyridine (2,2-bipy). The synthesized ligands and complexes were characterized by physical-chemical approaches including elemental analysis (CHN), infrared spectroscopy (IR), mass spectrometry, and flame atomic absorption spectroscopy. Additionally, a CSD search revealed that 397 complexes of pyridine-2,5-dicarboxylic acid (2,5-H2pydc) are reported, of which only 4 of them are derived from pyridine-2,5-dicarboxylic acid N-oxide

Flow shop scheduling problem with maintenance coordination: A new approach

Flow shop scheduling problem with maintenance coordination: A new approach

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Part of #Flow shop scheduling problem with maintenance coordination: A new approach# :

Publishing year : 2013

Conference : Tenth International Conference on Industrial Engineering

Number of pages : 6

Abstract: This research studies the coordination of production scheduling and maintenance planning in the flow shop scheduling environment. The problem is considered in a bi-objective form, minimizing the makeup as a production scheduling criterion and minimizing system unavailability as a maintenance planning criterion. The time interval between consecutive maintenance activities as well as the number of maintenance activities on each machine is assumed to be non-fixed. A mixed-integer programming formulation of the problem is presented. A special case of the problem, also referred to as single server maintenance, is also studied. A bi-objective on a colony system algorithm is presented to solve the problem in focus. Computational experiments are provided in two directions. Firstly, two scenarios are defined for the heuristic information part of the algorithm, using CDS and NEH heuristics. Experiments are provided to select the best scenario. Moreover, a local search is incorporated into the proposed algorithm and two scenarios are defined for this purpose. Some experiments are also provided to select the appropriate local search algorithm.

Data Fusion in on-line tool wear estimation monitoring using wavelet transform and artificial neural networks

Data Fusion in on-line tool wear estimation monitoring using wavelet transform and artificial neural networks

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Part of #Data Fusion in on-line tool wear estimation monitoring using wavelet transform and artificial neural networks# :

Publishing year : 2012

Conference : International Conference on Nonlinear Modeling and Optimization

Number of pages : 16

Abstract: It is known that the force sensor in the turning process is sensitive to the gradually increasing wear and tear. Based on this fact, this paper examines a tool wear estimation technique in turning through force signals. In this paper we applied wavelet analysis for tool condition monitoring (TCM). Wavelet analysis has been the most important tool for today's processing of non-stationary signal processing techniques. Based on the nature of the monitored signals, the wavelet approaches are introduced and the TCM is discussed for Fourier's wavelet analysis methods. According to the multiresolution, sparcity and localization properties of wavelet transform, literature is reviewed in three categories in TCM: time-frequency analysis of machining signal, feature extraction, and estimation tool wear. A neural network architecture similar to a standard one-hidden-layer feed forward neural network is used to relate sensor sensor measurements to wear on a chair. A novel teaching algorithm for such a network is developed. The performance of this new method is compared with the previously developed tool wearsessment method, which uses a separate feature extraction step. The proposed wavelet network can also be useful for developing signal processing schemes for manufacturing process monitoring, critical component monitoring, and product quality monitoring

Investigating The Effect of SDS Surfactant and a biosurfactant-producing bacterium MR01, on IFT in Iranian Carbonate Reservoirs

Investigating The Effect of SDS Surfactant and a biosurfactant-producing bacterium MR01, on IFT in Iranian Carbonate Reservoirs

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Part of #Investigating The Effect of SDS Surfactant and a biosurfactant-producing bacterium MR01, on IFT in Iranian Carbonate Reservoirs# :

Publishing year : 2010

Conference : Fourteenth International Conference on Oil, Gas and Petrochemicals

Number of pages : 8

Abstract: The oil recovery from carbonate reservoirs is very low by conventional technology. Injected water will not penetrate easily into the porous matrix, and therefore can not displace the oil in place of chemical and especially surfactant and biosurfactant flooding is and interested method in this situation due to its effect on interfacial tension (IFT) reduction. Many previous studies of the IFT behavior of surfactants have also been concentrated in rather low concentrations of NaCl, with little or no divalent ion present. The surfactant flooding of the iranian carbonate reservoir is still a diffcult proposition due to the harsh brie conditions and the structure of the carbonates reservoir. In this paper, we have investigated the effect of a chemical surfactant called sodium dodecyl sulfate SDS and an effective biosurfactant-producing bacterium P seudomon aeruginosa MR01, isolated from oil excavation areas in southern Iran for oil recovery and focused on its effect on IFT. In addition, a model is presented to predict IFT between the desired surfactant and aqueous solution at different temperatures and a wide range of surfactant concentrations.