Gonābād, Iran
Gonābād, Iran

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Pourhoseini S.H.,University of Gonabad | Naghizadeh N.,University of Gonabad
Journal of the Taiwan Institute of Chemical Engineers | Year: 2017

The present work investigates the effects of different concentrations of silver-water microfluid on the thermophysical properties, Brownian motion and heat transfer performance of a plate heat exchanger. For this purpose, an experimental system which included a CR14-45 COMER plate heat exchanger, five pt100 platinum resistance temperature sensors with temperature control system, two rotameters for flow rate indication and control, an insulated reservoir tank with two immersed heaters in it and a stainless steel centrifugal pump for circulating fluid was prepared. In the next step, silver microparticles were synthesized from AgNO3 and then 8L of silver-water microfluid was prepared with different concentrations in the range of 0-0.125wt% and their thermal conductivity, heat capacity and temperature difference rate were experimentally gauged. The results indicated that all the concentrations of silver-water microfluid (in the range of 0-0.125wt%) enhance thermal conductivity and heat transfer rate in comparison with base fluid (pure water). However, there is an optimum concentration for microfluid (0.03wt%) in which the rate of heat transfer reaches its maximum value. In this case, the heat transfer rate of microfluid is 9% higher than the base fluid. At high microparticles concentrations, due to coagulation effect, some of the silver particles quickly stick together and build deposits on the surface of the plate heat exchanger. Consequently, the concentration of the particles in the microfluid decreases and the enhancement of thermal conductivity (1.25% for 0.125wt%) lowers in comparison with the optimum state. Furthermore, at concentrations beyond the optimum, the slope of temperature difference rate in microfluid is negative and, therefore, the Brownian motion and particles movement diminish and the silver particles tend to sediment. Microparticles deposited on the plate heat exchanger surface contribute to additional heat transfer resistance and decrease the heat transfer coefficients in comparison with the optimum state. © 2017 Taiwan Institute of Chemical Engineers.

Pourhoseini S.H.,University of Gonabad | Moghiman M.,Ferdowsi University of Mashhad
Journal of Enhanced Heat Transfer | Year: 2014

Natural gas, as a major source of clean energy, has low thermal radiation. Because radiation transfers a considerable portion of heat generated by flame, improving the radiation characteristics of flame is necessary. The aim of this study was to investigate how the injection of small quantities of micro kerosene droplets into a natural-gas flame helps enhance the flame's thermal radiation and consequently its thermal efficiency. For this purpose, a micronozzle injected kerosene droplets into a natural-gas nonluminous flame. Using an IR filter, a digital camera, an S-type thermocouple, a calibrated thermopile, and image processing software, along with numerical modeling, the radiation properties of a flame were studied. The results show that the injection of kerosene droplets causes an increase of 52% and 11.75% in thermal radiation and efficiency, respectively. Also, mean flame temperature increases by no more than 8% whereas the mean flame emissivity coefficient increases remarkably. © 2014 by Begell House, Inc.

Norouzi M.,Ferdowsi University of Mashhad | Pakizeh M.,Ferdowsi University of Mashhad | Namvar-Mahboub M.,University of Gonabad
Desalination and Water Treatment | Year: 2016

In this study, functionalized multi-walled carbon nanotubes (F-MWCNTs) were used to modify the polyvinylidene fluoride (PVDF)/polyvinyl chloride (PVC) blend UF membrane via solution blending method. The effect of F-MWCNTs dosage (0–1%) on the properties and performance of PVDF/PVC/F-MWCNTs membranes was investigated. The prepared blend membranes were characterized by Fourier Transform Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Field Emission Scanning Electron Microscopy (FESEM), contact angle, and tensile strength techniques. Results showed that hydrophilicity of membranes was enhanced with increase of F-MWCNTs content. The performance of the membranes was evaluated in terms of pure water flux (PWF) and dextran filtration. The results showed that presence of F-MWCNTs in polymer matrix improved performance and antifouling properties of PVDF/PVC blend membrane. Accordingly, incorporation of 0.3–0.5 wt.% of F-MWCNTs represented maximum dextran rejection and permeate flux, respectively. © 2016 Balaban Desalination Publications. All rights reserved.

Dastbaz Z.,Ferdowsi University of Mashhad | Pakizeh M.,Ferdowsi University of Mashhad | Namvar-Mahboub M.,University of Gonabad
Desalination and Water Treatment | Year: 2016

In this study, the influence of functionalized multi-walled carbon nanotube (F-MWCNT), sodium dodecyl sulfate (SDS) on the characteristic and performance of polyacrylonitrile (PAN) membrane was studied. The mixed matrix membranes were prepared via solution blending and phase inversion methods. MWCNTs were acidified and then functionalized by amino group using microwave. Three dosage of F-MWCNT, i.e. 0.5, 1 and 2 wt.%, and two dosage of SDS, i.e. 2.5 and 5 wt.%, were used to prepare mixed matrix membranes. The as-prepared membranes were characterized by scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), contact angle, and Fourier transform infrared spectroscopy. The hydrophilicity and pure water flux increased with addition of both additives. Separation performance of Bovine serum albumin (BSA) was investigated in three different pHs (5, 7 and 9). The results showed that both additives enhanced performance parameters of pure PAN membrane. From the results it is found that 0.5 wt.% of F-MWCNT and 2.5 wt.% of SDS, are the optimum values to achieve maximum permeate flux and BSA rejection, respectively. © 2016 Balaban Desalination Publications. All rights reserved.

Mohammadzadeh Kakhki R.,University of Gonabad
Arabian Journal of Chemistry | Year: 2014

The unique properties of carbon fiber electrodes (CFEs) offer a number of particular advantages for their use in analytical applications. However, some pretreatment is usually necessary for the modification of the carbon surface. One of these methods is enzyme modification, that enzyme reactions in the surface of the electrode can be useful for the certain determinations. Also application of nanoparticles is very useful for modification and gives very interesting responses for the electrode in the determination of various analytes. Electrochemical oxidation of a carbon surface is one of the other methods for modification. With this work the morphology of the surface changes as well as increasing the coverage by various oxygen-containing functional groups. These groups can then interact and bind with other species introduced to the surface. The modification of the surface of carbon fiber electrodes is an interesting topic with many applications in the fields of analytical chemistry, environmental and health science, fuel cell and biofuel cell and many others. In this review article we discussed about the various modification methods for carbon fiber electrodes and applications of these CFEs. © 2014 The Author.

Mohammadzadeh kakhki R.,University of Gonabad | Assadi H.,University of Gonabad
Journal of Inclusion Phenomena and Macrocyclic Chemistry | Year: 2014

Capillary electrophoresis is an establishing separation technique for a wide spectrum of analytes, ranging from small inorganic ions to macromolecules and it provides reliable data, requires minimal sample preparation and offers a high degree of automation. Application of crown ethers in the capillary electrophoresis because of their unique characteristics is well established. In this review article we investigated on the application of crown ethers in organic and inorganic compounds separations. © 2014 Springer Science+Business Media Dordrecht.

Kakhki R.M.,University of Gonabad
Russian Journal of Applied Chemistry | Year: 2016

The surface structure of common graphite electrodes are suitable for electrochemical detection of various analytes due to their favorable properties such as good conductivity and resistance to environmental and chemical hazards. Also this material is cheap and available. Modifying the surface of electrode improves their ability for various determinations. Modifying graphite electrodes with nanoparticles has attracted lots of attention due to their unique characteristics. In this article we review applications of modified graphite electrodes with nanomaterials. © 2016, Pleiades Publishing, Ltd.

Mohammadzadeh Kakhki R.,University of Gonabad
Journal of Inclusion Phenomena and Macrocyclic Chemistry | Year: 2015

Compared to the traditional micron-sized supports used in separation process, nano-sized adsorbents possess quite good performance due to high specific surface area and the absence of internal diffusion resistance, which improve adsorption capacity. Recently, magnetic technology has been applied in pollution removal. Over the past few years, magnetic adsorption technology has attracted considerable attention for use in dye and metal removal. Magnetic nanoparticles are particularly attractive because of their inherent properties such as large surface area and fast response under applied external magnetic field. The high surface area to volume ratio and superparamagnetism of magnetic nanoparticles, combined with formation of complexes between adsorbent and β-cyclodextrins (β-CD), can effectively remove pollutants from wastewater. These nanoparticles modified with cyclodextrins also can be used in chiral separations. Therefore nowadays, efforts are being made to magnetic nanoparticle modified with CDs as efficient adsorbent in separations. © Springer Science+Business Media Dordrecht 2015.

Shahi H.,University of Gonabad | Ghavami R.,University of Shahrood | Rouhani A.K.,University of Shahrood
Journal of Geochemical Exploration | Year: 2016

The surface geochemical data in spatial domain can be transferred to frequency domain using two-dimensional Fourier transformation. The analysis of surface geochemical data in frequency domain has been led to the exploratory information which may be not achievable in the spatial domain of geochemical data. In this research, the frequency domain of surface geochemical data has been analyzed for recognizing the complex geochemical patterns related to ore deposits. In order to predict the variations of mineralization in the depth and identifying the blind mineral deposits, the developed Frequency Coefficients Method (FCM) has been proposed and applied in hidden Zafarghand Cu-Mo porphyry deposit. This proposed approach has desirably demonstrated the relationship between different frequencies in the surface geochemical distribution map and various depths of deposits. The results, obtained from applying the proposed technique to a real scenario, reveal significant improvements, compared to the results obtained from the spatial domain of geochemical data. The introduced method as a pattern recognition technique makes possible, without exploration drilling, the determination of mineralization trends in depth and the distinction between blind mineralization and dispersed ore mineralization zones. © 2015 Elsevier B.V.

Mohammadzadeh Kakhki R.,University of Gonabad | Rakhshanipour M.,University of Zabol
Arabian Journal of Chemistry | Year: 2015

There is a general need to develop simple, rapid, and inexpensive detection assays for diagnostic applications and environmental analysis. Currently, most analyses are performed under laboratory conditions, frequently with the assistance of expensive instruments and trained personnel. Colorimetric sensors as dipsticks or in a chromatographic format would be ideal for the various analyses. These sensors need minimal instrumentation and achieve high sensitivity. In recent years, metallic nanoparticles especially gold nanoparticles and silver nanoparticles have been widely used as colorimetric probes for chemical sensing and biosensing. This interesting application is due to their unique size-dependent, interparticle distance dependent, absorption spectra and solution color. When the nanoparticles approach each other and aggregate, the color of the nanoparticles changes from red to purple (or blue) for gold nanoparticles and from yellow to red (or dark green) for silver nanoparticles respectively. This phenomenon is due to the shift of the surface plasmon band to longer wavelength. Crown ethers are known for the unusual property of forming stable complexes with cations. The oxygen atoms lie in a nearly planar arrangement about the central cation. Today the development of crown ether functional nanoparticle as colorimetric sensors is a subject of considerable interest. In this article we investigated on the use of nanoparticle modified with crown ether for sensing of metal ions and also charged molecules with colorimetric technique. © 2015 The Authors.

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