To enhance interfacial bonding between carbon fibers and epoxy matrix, the carbon fibers have been modified with multiwall carbon nanotubes (MWCNTs) using the dip- coating technique. FT-IR spectrum of the MWCNTs shows a peak at 1640 cm−1 corresponding to the stretching mode of the C=C double bond which forms the framework of the carbon nanotube sidewall. The broad peak at 3430 cm−1 is due to O–H stretching vibration of hydroxyl groups and the peak at 1712 cm−1 corresponds to the carboxylic (C=O) group attached to the carbon fiber. The peaks at 2927 cm−1 and 2862 cm−1 are assigned to C–H stretching vibration of epoxy produced at the defect sites of acid-oxidized carbon fiber surface. SEM image shows a better interface bonding between the fiber and the matrix of modified composites (MWCNTs-CF/Ep) than those of unmodified composite. The loss factor curve of CF-MWCNTs/Ep composites is the narrowest compared with neat epoxy and CF/Ep composites which evinces that the length distribution range of molecular chain segments in the matrix is the narrowest. From the dependence of the AC conductivity on temperature, we can see that σAC increases when temperature increases. The increase in electrical conductivity of the composites may be a result of the increased chain ordering due to annealing effect. The use of MWCNTs to modify the surface of carbon fiber resulted in a large amount of junctions among MWCNT causing an increase in the electrical and thermal conductivity by forming conducting paths in the matrix. The MWCNTs-CF/Ep composite shows better thermal stability than unmodified composites. The strong interaction between CF and MWCNTs can retard diffusion of small molecules from the resin matrix at high temperature and hence, result in the improved thermal stability of the modified CF/Ep composite.
Heat transfer around a flat plate fin integrated with piezoelectric actuator used as oscillated fin in laminar flow has been studied experimentally utilizing thermal image camera. This study is performed
for fixed and oscillated single and triple fins. Different substrate-fin models have been tested, using fins of (35mm and 50mm) height, two sets of triple fins of (3mm and 6mm) spacing and three frequencies
applied to piezoelectric actuator (5, 30 and 50HZ). All tests are carried out for (0.5 m/s and 3m/s) in subsonic open type wind tunnel to evaluate temperature distribution, local and average Nusselt number (Nu) along the fin. It is observed, that the heat transfer enhancement with oscillation is significant compared to without o
This study was conducted at the poultry farm located in the College of Agricultural Engineering Sciences, University of Baghdad, Abu Gharib (the old site), and laboratories of the Animal Production Department, Jadriya, to investigate the effect of adding hydrogen peroxide H2O2 at nanoscale levels to semen diluents of local roosters sperm in a number of semen characteristics. In this study, 80 roosters local Iraqi chickens were used, the roosters were trained three times a week, to collect semen, until the largest number of them responded. Then the best 40 of the roosters were elected for the purpose of collecting the semen with a pooled sample, and then the samples were diluted and divided equally into four parts. The concentrations of 0, 1
... Show MoreDrought is a complex phenomenon that has severe impacts on the environment. Vegetation and its conditions are very sensitive to drought effects. This study aimed to monitor and assess the drought severity and its relationships to some ecological variables in ten districts of Erbil Governorate (Kurdistan Region), Iraq, throughout 20 years (1998-2017). The results revealed that droughts frequently hit Erbil throughout the study period. The Landsat time-series- based on Vegetation Condition Index (VCI) significantly correlated with precipitation, Digital Elevation Model (DEM), and latitude. Extreme VCI-based drought area percentages were recorded in 1999, 2000, 2008, and 2011 by 43.4%, 67.9%, 43.3%, and 40.0%, respe
... Show MoreThis research includes synthesis of new 5-Nitro isatin derivatives starting from 5-nitro-3-(imino acetohydrazide)-2-oxo indole (1) namely 5-nitro-3-[iminoaceto(tetra hydropyridazin-3,6-dione)-2-yl]-2-oxo indole (2); 5-nitro-3-[iminoaceto(hexahydrodiazepine-3,7-dione)-2-yl]-2-oxo indole (3); 5-nitro-3-[iminoaceto (1,2-dihydro pyridiazin-3,6-dione)-2-yl]-2-oxo indole (4); 5-nitro-3-[iminoaceto (8-nitro- 1,2-dihydrophtalazin-3,10-dione)-2-yl]-2-oxo indole (5) and 5-nitro-3-[iminoaceto (1,2-dihydrophtalazin-3,10-dione)-2-yl]-2-oxo indole (6). The derivatives were characterized using FTIR, 1HNMR, 13CNMR and C.H.N.S analy
... Show MoreIn the present work, HgBa2Can-1CunO2n+2+δ superconducting thin films with (100) nm thickness were (n=1, 2 and 3) prepared by Pulsed Laser Deposition technique on glass substrate at R.T (300) K, have been synthesize. The effect of Cu content on the structural, surface morphology, optical and electrical properties of HgBa2Can-1CunO2n+2+δ films were investigated and analyzed. The results of XRD analysis show that all samples are polycrystalline structure with orthorhombic phase, the change of Cu concentration in samples produce changes in the mass density, lattice parameter and the ratio (c/a). AFM techniques were used to examine the surface morphology of HgBa2Can-1CunO2n+2+δ superconducting films, the study showed the values of surface rou
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