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21.
Moharramnejad Mojtaba Ehsani Ali Malekshah Rahime Eshaghi Shahi Mehrnaz Bavandpour Razieh Rajabi Hamidreza Mojab Seyyed Mohammadreza 《Journal of Materials Science: Materials in Electronics》2022,33(25):19693-19710
Journal of Materials Science: Materials in Electronics - This review gives an overview of the synthesis, surface, and electrochemical investigations over Mn-based compounds in the development of... 相似文献
22.
Rad Abdolvahab Ehsani Rahim Mohd Shafry Mohd Kolivand Hoshang Norouzi Alireza 《Multimedia Tools and Applications》2018,77(21):28843-28862
Multimedia Tools and Applications - Dental diseases have high risk of affection across the globe and mostly in adult population. The analysis of dental X-ray images has some difficulties in... 相似文献
23.
Comparison of pristine and polyaniline‐grafted MWCNTs as conductive sensor elements for phase change materials: Thermal conductivity trend analysis
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Maryam Halvaee Khadijeh Didehban Vahabodin Goodarzi Mehdi Ghaffari Morteza Ehsani Mohammad Reza Saeb 《应用聚合物科学杂志》2017,134(47)
Phase change materials (PCMs) function based on latent heat stored on or released from a substance over a slim temperature range. Multiwalled carbon nanotubes (MWCNTs) and polyaniline are important elements in sensor devices. In this work, pristine and polyaniline‐grafted MWCNTs (PANI‐g‐MWCNTs) were applied as conductive carbon‐based fillers to make PCMs based on paraffin. The attachment of PANI to the surface of MWCNTs was proved by Fourier transform Infrared analysis. Dispersion of MWCNTs in paraffin was studied by wide‐angle X‐ray scattering. Heating and solidification of PCM nanocomposites were investigated by differential scanning calorimetry, while variation in nanostructure of PCMs during heating/solidification process was evaluated by rheological measurements. It was found that after 30 min of sonication, the samples filled with 1 wt % MWCNTs have melting and solidification temperatures of 29 and 42 °C, respectively. It was also found that PANI attachment to MWCNTs significantly changes thermal conductivity behavior of PCM nanocomposites. The developed MWCNTs‐based sensor elements responded sharply at low MWCNTs content, and experienced an almost steady trend in conductivity at higher contents, while PANI‐g‐MWCNTs sensor followed an inverse trend. This contradictory behavior brought insight for understanding the response of PCMs against thermal fluctuations. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45389. 相似文献
24.
Interrelationship of thermal and mechanical properties of poly(ethylene terephthalate)/poly(ethylene 2,6‐naphthalate)/graphene nanocomposites
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In the present work, attempts were made to investigate the thermal and mechanical properties of melt‐processed poly(ethylene terephthalate) (PET)/poly(ethylene 2,6‐naphthalate) (PEN) blends and its nanocomposites containing graphene by using differential scanning calorimetry and tensile test experimenting. The results showed that crystallinity, which depends on a blend ratio, completely disappeared in a composition of 50/50. By introducing graphene to PET, even in low concentrations, the crystallinity of samples increased, while the nanocomposite of PEN indicated reverse behavior, and the crystallinity was reduced by adding graphene. In the case of PET‐rich (75/25) nanocomposite blends, by increasing the nano content in the blend, the crystallinity of the samples was enhanced. This behavior was attributed to the nucleating effect of graphene particles in the samples. From the results of mechanical experiments, it was found in PET‐rich blends that by increasing the PEN/PET ratio, the modulus of samples decreased, whereas in the case of PEN‐rich blends, a slight increment of modulus is seen as a result of the increment of the PEN/PET ratio. The two contradicting behaviors were attributed to the reduction of crystallinity of PET‐rich blends by enhancement of PEN/PET ratio and the rigid structure of PEN chains in PEN‐rich blends. Unlike the different modulus change of PET‐rich and PEN‐rich blends, the nanocomposites of these blends similarly indicated an increment of modulus and characteristics of rigid materials by increasing the nano content. Furthermore, the same behavior was detected in nanocomposites of each polymer (PET and PEN nanocomposites). The alteration from ductile to rigid conduction was related to the impedance in the role of graphene plates against the flexibility of polymer chains and high values of graphene modulus. J. VINYL ADDIT. TECHNOL., 23:210–218, 2017. © 2015 Society of Plastics Engineers 相似文献
25.
M. R. Ehsani H. Saadatmanesh J. I. Velazquez-Dimas 《Canadian Metallurgical Quarterly》1999,3(3):134-142
Unreinforced masonry (URM) buildings perform poorly under seismic forces and have been identified as the main cause of loss of life in recent earthquakes. Many of these structures fail in out-of-plane bending due to the lack of reinforcement. In this study, the experimental results from three half-scale unreinforced brick walls retrofitted with vertical composite strips are presented. The specimens were subjected to cyclic out-of-plane loading. Five reinforcement ratios and two different glass fabric composite densities were investigated. The mode of failure is controlled by tensile failure when wider and lighter composite fabrics are used and by delamination when stronger ones are used. The tested specimens were capable of supporting a lateral load up to 32 times the weight of the wall. A deflection as much as 2% of the wall height was measured. Although both URM walls and composite strips behave in a brittle manner, the combination resulted in a system capable of dissipating some energy. Retrofitting URM walls with composite strips proved to be a good and reliable strengthening alternative. 相似文献
26.
Comparison of pH-dependent sonodisruption of re-assembled casein micelles by 35 and 130 kHz ultrasounds 总被引:1,自引:0,他引:1
Ashkan Madadlou Mohammad Ebrahimzadeh Mousavi Zahra Emam-Djomeh Mohammadreza Ehsani David Sheehan 《Journal of food engineering》2009,95(3):505-509
Sonodisruption behavior of re-assembled casein micelles was compared at two ultrasound frequencies (35 and 130 kHz) by turbidity measurement and laser-diffraction based particle size analysis. Sonochemical ultrasound (130 kHz) was more effective than power ultrasound (35 kHz) in micelle disruption. This was attributed to the higher strain rates generated upon implosion of cavities, as well as the liberation of more free radicals to the surrounding medium. The higher the pH of solution, the more effective was the ultrasonic disruption due to a looser expanded assembly of particles at higher pH values. Sonochemical ultrasound decreased the consistency coefficient of casein solutions and increased their flow index except at a pH value of 6.35, while power ultrasound did not affect the flow behavior of solutions across the whole pH range. 相似文献
27.
M. H. Ehsani M. E. Ghazi P. Kameli F. S. Razavi 《Journal of Superconductivity and Novel Magnetism》2013,26(10):3151-3157
The Co-doped bilayered LaSr2Mn2O7 manganite at low Co concentrations (0–0.15) was synthesized by the sol–gel process. The X-ray diffraction (XRD) technique confirms phase formation for all the samples under investigation. The results of ac magnetic susceptibility measurements indicate the effect of Co doping on the magnetic ordering phases. The indications of charge ordering (CO) transitions were observed in all the prepared compounds. The CO magnetic phase transition temperature was observed systematically shift to lower temperatures as the Co concentration increases. There was an anomalous oscillating magnetic behavior in all samples with a few peaks before the CO temperature in the paramagnetic (PM) region so that with an increasing Co doping, the number of peaks and amplitude were decreased. Also, the ac susceptibility measurements were performed in the presence of an applied dc magnetic field to further study of this oscillating behavior. 相似文献
28.
29.
Ahmad Mani-Varnosfaderani Samaneh Ehsani Yadollah Yamini 《Petroleum Science and Technology》2013,31(24):2374-2382
AbstractIn this study, we focused on combination of gas chromatography and chemometrics techniques for relating the viscosity indices (VI) of motor oils to their chemical compositions. Partial least square (PLS) algorithm was used for relating the retention times of the collected chromatograms to VI of motor oils. The constructed model showed acceptable statistical values which indicate the robustness of the developed PLS model. GC-MS analysis was used for identification of the important chemicals affecting the values of VIs. Nonane, Pentafluoropropionic acid, Phthalic acid, nonylphenol and Tetracosane were suggested to have positive impacts on the values of VIs of motor oils. 相似文献
30.
H.R. Baharvandi N. Talebzadeh N. Ehsani F. Aghand 《Journal of Materials Engineering and Performance》2009,18(3):273-277
Production of (B4C-nano TiB2) composite powder by chemical method was evaluated in this study. Starting materials were boron carbide, carbon, and titanium
(IV) iso propoxide (TTIP). Water was used as a hydrolyser agent. TTIP was hydrolyzed with water and, consequently, amorphous
Ti(OH)4 was formed. Heat-treatment of Ti(OH)4 at 100 and 850 °C led to the production of TiO2 and TiB2 phases, respectively. The effect of heat-treatment time and temperature on the phase transformation and size of the produced
nano powder were investigated. The produced nano powder was characterized by XRD, SEM, and DTA. It was found that heat-treatment
time and temperature have significant effects on the amount and size of the produced TiB2 powder. The data also reveal that the minimum temperature for TiB2 formation is 650 °C. 相似文献