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Search Results: 1 - 10 of 2346 matches for " Seyed Schwan Hosseiny "
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Surface Initiated Polymerizations via e-ATRP in Pure Water
Seyed Schwan Hosseiny,Patrick van Rijn
Polymers , 2013, DOI: 10.3390/polym5041229
Abstract: Here we describe the combined process of surface modification with electrochemical atom transfer radical polymerization ( e-ATRP) initiated from the surface of a modified gold-electrode in a pure aqueous solution without any additional supporting electrolyte. This approach allows for a very controlled growth of the polymer chains leading towards a steady increase in film thickness. Electrochemical quartz crystal microbalance displayed a highly regular increase in surface confined mass only after the addition of the pre-copper catalyst which is reduced in situ and transformed into the catalyst. Even after isolation and washing of the modified electrode surface, reinitiation was achieved with retention of the controlled electrochemical ATRP reaction. This reinitiation after isolation proves the livingness of the polymerization. This approach has interesting potential for smart thin film materials and offers also the possibility of post-modification via additional electrochemical induced reactions.
Friedel–Crafts Crosslinked Highly Sulfonated Polyether Ether Ketone (SPEEK) Membranes for a Vanadium/Air Redox Flow Battery
Géraldine Merle,Filipoi Carmen Ioana,Dan Eugen Demco,Michel Saakes,Seyed Schwan Hosseiny
Membranes , 2014, DOI: 10.3390/membranes4010001
Abstract: Highly conductive and low vanadium permeable crosslinked sulfonated poly(ether ether ketone) (cSPEEK) membranes were prepared by electrophilic aromatic substitution for a Vanadium/Air Redox Flow Battery (Vanadium/Air-RFB) application. Membranes were synthesized from ethanol solution and crosslinked under different temperatures with 1,4-benzenedimethanol and ZnCl 2 via the Friedel–Crafts crosslinking route. The crosslinking mechanism under different temperatures indicated two crosslinking pathways: (a) crosslinking on the sulfonic acid groups; and (b) crosslinking on the backbone. It was observed that membranes crosslinked at a temperature of 150 °C lead to low proton conductive membranes, whereas an increase in crosslinking temperature and time would lead to high proton conductive membranes. High temperature crosslinking also resulted in an increase in anisotropy and water diffusion. Furthermore, the membranes were investigated for a Vanadium/Air Redox Flow Battery application. Membranes crosslinked at 200 °C for 30 min with a molar ratio between 2:1 (mol repeat unit:mol benzenedimethanol) showed a proton conductivity of 27.9 mS/cm and a 100 times lower VO 2+ crossover compared to Nafion.
Possible Central Extensions of Non-Relativistic Conformal Algebras in 1+1
Ali Hosseiny
Mathematics , 2014, DOI: 10.1063/1.4884415
Abstract: We investigate possibility of central extension for non-relativistic conformal algebras in 1+1 dimension. Three different forms of charges can be suggested. A trivial charge for temporal part of the algebra exists for all elements of l-Galilei algebra class. In attempt to find a central extension as of CGA for other elements of the l-Galilei class, possibility for such extension was excluded. For integer and half integer elements of the class we can have an infinite extension of the generalized mass charge for the Virasoro-like extended algebra. For finite algebras a regular charge inspired by Schr\"odinger central extension is possible.
Violation of Invariance of Measurement for GDP Growth Rate and its Consequences
Ali Hosseiny
Quantitative Finance , 2015,
Abstract: The aim here is to address the origins of sustainability for the real growth rate in the United States. For over a century of observations on the real GDP per capita of the United States a sustainable two percent growth rate has been observed. To find an explanation for this observation I consider the impact of utility preferences and the effect of mobility of labor \& capital on every provided measurement. Mobility of labor results in heterogenous rates of increase in prices which is called Baumol's cost disease phenomenon. Heterogeneous rates of inflation then make it impossible to define an invariant measure for the real growth rate. Paradoxical and ambiguous results already have been observed when different measurements provided by the World Bank have been compared with the ones from the central banks. Such ambiguity is currently being discussed in economy. I define a toy model for caring out measurements in order to state that this ambiguity can be very significant. I provide examples in which GDP expands 5 folds while measurements percept an expansion around 2 folds. Violation of invariance of the measurements leads to state that it is hard to compare the growth rate of GDP for a smooth growing country such as the U.S. with a fast growing country such as China. Besides, I state that to extrapolate the time that economy of China passes the economy of the US we need to consider local metric of the central banks of both countries. Finally I conclude that it is our method of measurements that leads us to percept the sustainable growth rate.
Affine Extension of Galilean Conformal Algebra in 2+1 Dimensions
Ali Hosseiny,Shahin Rouhani
Mathematics , 2009, DOI: 10.1063/1.3371191
Abstract: We show that a class of nonrelativistic algebras including non centrally-extended Schrodinger algebra and Galilean Conformal Algebra (GCA) has an affine extension in 2+1 hitherto unknown. This extension arises out of the conformal symmetries of the two dimensional complex plain. We suggest that this affine form may be the symmetry that explains the relaxation of some classical phenomena towards their critical point. This affine algebra admits a central extension and maybe realized in the bulk. The bulk realization suggests that this algebra may be derived by looking at the asymptotic symmetry of an AdS theory. This suggests that AdS/CFT duality may take on a special form in four dimensions.
Numerical study on spectral domain optical coherence tomography spectral calibration and re-sampling importance
Hamid Hosseiny,Carla Carmelo Rosa
Photonic Sensors , 2013, DOI: 10.1007/s13320-012-0093-0
Abstract: A spectral calibration technique, a data processing method and the importance of calibration and re-sampling methods for the spectral domain optical coherence tomography system were numerically studied, targeted to optical coherence tomography (OCT) signal processing implementation under graphics processing unit (GPU) architecture. Accurately, assigning the wavelength to each pixel of the detector is of paramount importance to obtain high quality images and increase signal to noise ratio (SNR). High quality imaging can be achieved by proper calibration methods, here performed by phase calibration and interpolation. SNR was assessed employing two approaches, single spectrum moving window averaging and consecutive spectra data averaging, to investigate the optimized method and factor for background noise reduction. It was demonstrated that the consecutive spectra averaging had better SNR performance.
Measurements of non-linear optical constants of chalcogenide glasses using Z-scan and the degenerate four wave mixing (DFWM) techniques
A. Zakery,B. Hosseiny,S. E. Pourmand
Iranian Journal of Physics Research , 2005,
Abstract: Chalcogenide glasses such as arseic sulfide(As2 S3 ) have attracted attention for applications such as all-optical switching in high speed communication. This is due to their high non-linear refractive-index. Z-scan and the Degenerate four wave mixing (DFWM) techniques can be used to measure the non-linear refractive index n 2 and the two photon absorption coefficient β . A simaltanous closed-aperture and open-aperture Z-scan experimental set up was used to obtain the experimental results. The results were then fitted into a theoretical formula. Values of n2=3×10-17m2/W and β= 0.29 cm/GW have been obtained. DFWM measurements were made on arsenic sulfide films. A Box-cars forward geometry was used in these measurements. Experimental results based on non-phase matched signals were again fitted into a theoretical formula and a value of n2 =3.9×10-17 m2 /W was obtained .
Logarithmic Exotic Conformal Galilean Algebras
Malte Henkel,Ali Hosseiny,Shahin Rouhani
Physics , 2013, DOI: 10.1016/j.nuclphysb.2013.12.009
Abstract: Logarithmic representations of the conformal Galilean algebra (CGA) and the Exotic Conformal Galilean algebra ({\sc ecga}) are constructed. This can be achieved by non-decomposable representations of the scaling dimensions or the rapidity indices, specific to conformal galilean algebras. Logarithmic representations of the non-exotic CGA lead to the expected constraints on scaling dimensions and rapidities and also on the logarithmic contributions in the co-variant two-point functions. On the other hand, the {\sc ecga} admits several distinct situations which are distinguished by different sets of constraints and distinct scaling forms of the two-point functions. Two distinct realisations for the spatial rotations are identified as well. The first example of a reducible, but non-decomposable representation, without logarithmic terms in the two-point function is given.
Preconcentration of Lead in Sugar Samples by Solid Phase Extraction and Its Determination by Flame Atomic Absorption Spectrometry  [PDF]
Saied Saeed Hosseiny Davarani, Neda Sheijooni-Fumani, Amin Morteza Najarian, Mohammad-Ali Tabatabaei, Siavash Vahidi
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.25071
Abstract: A simple and sensitive solid phase extraction utilizing C18 filled cartridges incorporated with dithizone for preconcentration of lead and its subsequent determination by flame atomic absorption spectrometry (FAAS) was developed. Several parameters such as type, concentration and volume of eluent, pH of the sample solution, flow rate of extraction and volume of the sample were evaluated. The effect of a variety of ions on preconcentration and recovery was also investigated. At pH = 7.4 and 1.0 mol?L–1 HCl eluting them, lead ions were recovered quantitatively. The limit of detection (LOD) defined as 3Sbl was determined to be 8.1 μg L–1 for 500 mL of sample solution and eluted with 5 mL of 1.0 mol?L–1 HCl under optimum conditions. The accuracy and precision (RSD %) of the method were >90% and <10%, respectively. In the end, the proposed method was applied to a number of real sugar samples and the amount of lead was determined by spiking a known concentration of lead into the solution.
Metal ion–binding properties of the L-aspartic acid and tartaric acid, a coparative investigation. How can be increased the dosage of mineral absorption in the body  [PDF]
Seyed Ali Akbar Sajadi
Advances in Bioscience and Biotechnology (ABB) , 2010, DOI: 10.4236/abb.2010.14047
Abstract: A comparative research has been developed for acidity and stability constants of M(TTA)1 and M(Asp)2 complexes which have been determined by potentiometric pH titration. Depending on metal ion–binding properties, vital differences in building complex were observed. The present study shows that in M(TTA) complexes, metal ions are coordinated to the carboxyl groups, but in M(Asp) some metal ions are able to build macrochelate over amine group. Hence, the following intermolecular and as a result independent concentration equilibrium between an open–isomer M(Asp)op and a closed–isomer M(Asp)cl, has to be considered cl op. The amounts are reported. The results mentioned above demonstrate that for some M(Asp) complexes the stability constants is also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions and transfer them via building complexes with the aspartate. The result of this effect is a higher dosage-absorption of minerals in body. Based on the sort of metal ions, the drug-therapy can be different. For heavy metal ions this building complex helps the absorption and filtration of the blood plasma, and consequently the excursion of heavy metal ions takes place. This is an important method in microdialysis. Other metal ions such as the complexes can be considered as mineral carriers. These complexes in certain conditions (PH–range) can release the minerals in body.
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