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.
KHalaf Alhmar and what we get from his poem
Background The escalating global concern over increased body weight in adolescents, coupled with the rising rates of adolescent pregnancy worldwide, presents a significant challenge to healthcare systems. We plan to identify the maternal and neonatal consequences associated with pre-pregnancy overweight in adolescent women. Methods Throughout five years, all singleton adolescent pregnant women with pre-pregnancy self-reported body mass index (BMI) of 18.5– ≤ 29.9 were involved during the first-trimester visit. Two groups were generated: overweight and appropriate-weight (BMI 25–29.9 and 18.5–24.9, respectively). Obstetric and neonatal outcomes were observed prospectively and statistically adjusted for the confounding factors.
... Show MoreThe aim of this study to investigate the sexual harassment, prevention strategies, and the appropriate ways that tackle this phenomena. The current research consisted of four chapter; the first chapter gave a general introduction about the targeted topic followed by the problem of statement, the significance of study, study’s aims, and end with the limitations of study. The second section of chapter one referred to the common concepts of study. Third section addressed the previous studies that related to the current one. Chapter two concerned with the sexual violence against minors. It has four section; first section addressed number of concepts which related to sexual violence. The second section focused on the implications of sexual
... Show MorePhysicians are infrequently selected to serve in the yearlong role of Jefferson Science Fellow (JSF) as senior science advisor for the US Department of State or the United States Agency for International Development. The authors discuss the role of a JSF in promoting “science diplomacy” from the perspective of one alumnus, who sites examples of ongoing, long-term collaborative projects including one focusing on medical education reform in Iraq that would not have been possible without the JSF program. More than 3 decades of political and social unrest, terrorism, the internal displacement of millions of Iraqi citizens, the arrival of Syrian refugees, international sanctions, and the effect of fluctuating oil prices that fund education i
... Show MoreFor any group G, we define G/H (read” G mod H”) to be the set of left cosets of H in G and this set forms a group under the operation (a)(bH) = abH. The character table of rational representations study to gain the K( SL(2,81)) and K( SL(2, 729)) in this work.
In this study, a fast block matching search algorithm based on blocks' descriptors and multilevel blocks filtering is introduced. The used descriptors are the mean and a set of centralized low order moments. Hierarchal filtering and MAE similarity measure were adopted to nominate the best similar blocks lay within the pool of neighbor blocks. As next step to blocks nomination the similarity of the mean and moments is used to classify the nominated blocks and put them in one of three sub-pools, each one represents certain nomination priority level (i.e., most, less & least level). The main reason of the introducing nomination and classification steps is a significant reduction in the number of matching instances of the pixels belong to the c
... Show MoreBackground: Pyogenic discitis most frequently occurs
after home delivery, hemorridectomy, and dilatation and
curettage. Discitis is generally due to blood borne bacterial
invasion of the disc from adjacent end-plate via
communicating vessels. Infective discitis remains an
uncommon, but potentially serious cause for back pain.
Delayed diagnosis can occur and a high index of suspicion
may occur.
Methods: The study included 30 patients suffering from
localized low back pain with limitation of movement.
Diagnosis was made by history, physical examination and
investigation mainly E.S.R and MRI.
Results: 50.3% of patient with discitis had a history of
vaginal delivery, 15% had a history of hemorridectomy
Agent technology has a widespread usage in most of computerized systems. In this paper agent technology has been applied to monitor wear test for an aluminium silicon alloy which is used in automotive parts and gears of light loads. In addition to wear test monitoring، porosity effect on
wear resistance has been investigated. To get a controlled amount of porosity, the specimens have
been made by powder metallurgy process with various pressures (100, 200 and 600) MPa. The aim of
this investigation is a proactive step to avoid the failure occurrence by the porosity.
A dry wear tests have been achieved by subjecting three reciprocated loads (1000, 1500 and 2000)g
for three periods (10, 45 and 90)min. The weight difference a
Recently, the development and application of the hydrological models based on Geographical Information System (GIS) has increased around the world. One of the most important applications of GIS is mapping the Curve Number (CN) of a catchment. In this research, three softwares, such as an ArcView GIS 9.3 with ArcInfo, Arc Hydro Tool and Geospatial Hydrologic Modeling Extension (Hec-GeoHMS) model for ArcView GIS 9.3, were used to calculate CN of (19210 ha) Salt Creek watershed (SC) which is located in Osage County, Oklahoma, USA. Multi layers were combined and examined using the Environmental Systems Research Institute (ESRI) ArcMap 2009. These layers are soil layer (Soil Survey Geographic SSURGO), 30 m x 30 m resolution of Digital Elevati
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