Polyimide/MWCNTs nanocomposites have been fabricated by solution mixing process. In the present study, we have investigated electrical conductivity and dielectric properties of PI/MWCNT nanocomposites in frequency range of 1 kHz to 100 kHz at different MWCNTs concentrations from 0 wt.% to 15 wt.%. It has been observed that the electrical conductivity and dielectric constants are enhanced significantly by several orders of magnitude up to 15 wt.% of MWCNTs content. The electrical conductivity increases as the frequency is increased, which can be attributed to high dislocation density near the interface. The rapid increase in the dielectric constant at a high MWCNTs content can be explained by the formation of a percolative path of the conducting network through the sample for a concentration corresponding to the percolation threshold. The high dielectric constant at a low frequency (1 kHz) is thought to originate from the space charge polarization mechanism. I-V characteristics of these devices indicate a significant increase in current with an increase in multi-walled carbon nanotube concentration in the composites. The SEM images show improved dispersion of MWCNTs in the PI matrix; this is due to the strong interfacial interactions.
Differences in transversal sections and activities of geomorphological operations led to forming geomorphological shapes as river turns and river isles in watercourse in the area of study. The study showed three river turns that are Sindia turn with length 4723m, turn wave 3599 average width 267.6, Zanbour turn length 11374m, turn wave 7110 average width 307.5m,and Dojama turn with length 5876m, turn wave 4982m average width 313.4m. This difference is caused by the activity of erosion and sedimentation that led to the appearance of the length rivers turn.
The study showed that the turn of Dojama is the only corresponding turn, whereas the phenomena of corresponding never appeared in other turns in the area of study. The study also sho
The means of communication in the accepted human contexts depend on several modes, beginning with the oldest of which in history, represented by the sign language, the sign and the symbol and ending with it, until countless of them became icons that are circulating between the societies themselves or with their neighbors. These icons are often implied in formations that represent a visual discourse which the sender uses as a means and as a message at the same time to express a certain phenomenon in society or in his human self, and thus the sender or performer or artist, in the end, adopted a visual intermediary in order to position his speech in its entirety and perhaps in a specific part of it, to carry the content of that speech and c
... Show MoreA qualitative chemical test was performed on functional groups extracted from fenugreek plant and its extracts (aqueous, alcoholic and volatile oil). Results revealed that fenugreek seeds contain the main functional groups, while extracts are varied accorodihg to their content of functional groups qualitatively and quantitively. Moreover, inhibition activity was tested for extracts of fenugreek seeds (aqueous, alcoholic and volatile oil). against gram negative (Salmonella typhimurium, Escherichia coli and Pseudomonas aeruginosa) and gram positive (Staphylococcus aureus) by the ager well diffusion method. Data have revealed that inhibition activity was different in accoradance with extract solvent and the tested microorgan. Oil extract (15)%
... Show MoreReproduction potential and age –specific fecundity of the Mealybug Planococcus citri Risso were studied in the laboratories of Biological control research unit,college of Agriculture –Baghdad university at 25± 2Cº and 60-70% R.H.with 16 light:8 dark photo period.The results showed that the survival ratio began to decline at the 38th day, the average female age was 20 days ,while the average age was 8 days at the first reproduction . Net reproduction rate ( Ro ) was 58.59 female female generation which prove that the population of the mealybug was of the unstable kind , intrinsic rate of increase (rm) was 0.118 femalefemale and the average length period of generation ( T ) was 34.30 days . Many local predators attack the mealybug
... Show MoreSphingolipids are key components of eukaryotic membranes, particularly the plasma membrane. The biosynthetic pathway for the formation of these lipid species is largely conserved. However, in contrast to mammals, which produce sphingomyelin, organisms such as the pathogenic fungi and protozoa synthesize inositol phosphorylceramide (IPC) as the primary phosphosphingolipid. The key step involves the reaction of ceramide and phosphatidylinositol catalysed by IPC synthase, an essential enzyme with no mammalian equivalent encoded by the AUR1 gene in yeast and recently identified functional orthologues in the pathogenic kinetoplastid protozoa. As such this enzyme represents a promising target for novel anti-fungal and anti-protozoal drugs. Given
... Show MoreIn this study, vegetable tanned leather waste of cow (VTLW-C) is used as adsorbent for removing methyl violet 10B dye from aqueous solution. The VTLW-C adsorbent was characterized by FTIR and SEM in order to evaluate its surface properties before using in adsorption experiments. Batch adsorption method was applied to study the effect of different factors such as weight of leather waste, time of shaking, and starting concentration of methyl violet 10B dye. Different isothermal models such as Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D–R) were used to analyze the experimental data. Kinetic study proceeds using (PFO) kinetic model and (PSO) kinetic model. The results showed better agreement with the Freundlich model; this means
... Show MoreBeta-lactam medications are among the commonly used antibiotics. These drugs kill germs by disrupting cell wall formation. This drug treats bacterial infections in numerous body sections. A new, quick, high-performance liquid chromatography approach has been developed and verified by the FDA and EMA for the simultaneous estimation of drugs in their medicinal and pure forms. This study deals with the determination of beta-lactam drugs (Amoxicillin, Ampicillin, Cephalexin, Cefotaxime, Cefoxitin, Cefamandole, Cephalothin, Piperacillin, Penicillin, Oxacillin, Cloxacillin, Nafcillin, Carbenicillin, Mezlocillin, Dicloxacillin) by a Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) technique based on an UV detector using a
... Show MoreThe increase in population resulted in an increase in the consumption of water. The present work investigates the performance of a recycling solar- powered greywater treatment system for the purposes of irrigation, used to reduce the amount of waste grey water and reduce electricity consumption and reduce the costs of constructing large scale water treatment plants. The system consumes about 3814W per hour and provides water treatment about 1.4 m3 per day. The proposed system is designed to residential, office and governmental buildings application. Tests are conducted in an office building at the Ministry of Science and Technology site in Baghdad. Laboratorial water samples testing analyses are co
... Show MoreIn this paper, Bayes estimators of the parameter of Maxwell distribution have been derived along with maximum likelihood estimator. The non-informative priors; Jeffreys and the extension of Jeffreys prior information has been considered under two different loss functions, the squared error loss function and the modified squared error loss function for comparison purpose. A simulation study has been developed in order to gain an insight into the performance on small, moderate and large samples. The performance of these estimators has been explored numerically under different conditions. The efficiency for the estimators was compared according to the mean square error MSE. The results of comparison by MSE show that the efficiency of Bayes est
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