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Preparation and electrical properties of polyimide/carbon nanotubes composites
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Abstract<p>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.</p>
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Publication Date
Sun Jan 13 2019
Journal Name
Iraqi Journal Of Physics
Effect of tempering on thermal analysis of Al-Ti-Si alloy and its composites
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The investigation of the effect of tempering on thermal analysis of
Al-Ti-Si alloy and its composites with MgO and SiC particles was
performed. Thermal analysis was performed before and after
tempering by DSC scan. Optical microscopy was used to identify the
phases and precipitations that may be formed in base alloy and
composites. X-ray diffraction test indicated that the Al3Ti is the main
phase in Al-Ti-Si alloy in addition to form Al5Ti7Si12 phase. Some
chemical reactions can be occurred between reinforcements and
matrix such as MgO.Al2O3 in Al-Ti/MgO, and Al4C3 and Al(OH)3 in
Al-Ti/SiC composite. X-ray florescence technique is used to
investigate the chemical composition of the fabricated specimens.
H

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Publication Date
Fri Jan 01 2016
Journal Name
The International Scientific Conference For Nanotechnology And Advance Research’s
Effect of the annealing and compositional on the Morphological and electrical
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Nanocrystalline TiO 2 and CuO doped TiO 2 thin films were successfully deposited on suitably cleaned glass substrate at constant room temperature and different concentrations of CuO (0.05,0.1,0.15,0.2) wt% using pulse laser deposition(PLD) technique at a constant deposition parameter such as : (pulse Nd:YAG laser with λ=1064 nm, constant energy 800 mJ, with repetition rate 6 Hz and No. of pulse (500). The films were annealed at different annealing temperatures 423K and 523 K. The effect of annealing on the morphological and electrical properties was studied. Surface morphology of the thin films has been studied by using atomic force microscopes which showed that the films have good crystalline and homogeneous surface. The Root M

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Publication Date
Mon Feb 10 2025
Journal Name
Journal Of Baghdad College Of Dentistry
The effect of adding single walled carbon nanotube with different concentrations on mechanical properties of heat cure acrylic denture base material
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Background: The most widely used material for fabrication of denture base is poly methyl methacrylate, despite its popularity, the main problems associated with it as a denture base material are poor strength particularly under fatigue failure inside the patient mouth, impact failure outside the patient mouth, which are the main causes for fracture of denture, several studies was done to increase mechanical properties of denture base. The present study was conducted to evaluate and compare the effect of addition single walled carbon nanotubes in different concentrations to polymethyl methacrylate on some mechanical properties (surface hardness, surface roughness, impact strength and transverse strength). Materials and methods: Forty eight

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Publication Date
Mon Feb 25 2019
Journal Name
Iraqi Journal Of Physics
Dielectric behavior and AC electrical conductivity analysis of PMMA films
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PMMA films of different thickness (0.006, 0.0105, 0.0206, 0.0385 and 0.056cm) were synthesized by casting process. The temperature and frequency dependence of dielectric constant and AC electrical conductivity measurements at various frequencies (10kHz-10MHz) and temperatures (293-373K) were carried out. Few anomalies in dielectric studies were observed near 313 and 373 K respectively. These points were related to glass transitions temperature. The variation of activation energy and conduction behavior was studied .From the AC conduction studies, it is confirmed that the mechanism responsible for the conduction process is hopping of carriers. The variations of the dielectric constant and loss as function of frequency at different tempera

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Publication Date
Tue Jan 08 2019
Journal Name
Iraqi Journal Of Physics
D.C electrical conductivity of prepared pure and doped polyaniline salt
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Pure Polyaniline salt, and protonation PANI by H2SO4 were synthesized by electro-chemical oxidative polymerization of aniline with acidity of H2SO4. The solution was prepared in reaction temperature equal 291 K and the acidity of aqueous solution was 1 molarities. The prepared polyaniline was characterized by FT-IR, the result indicate that the intensity is increase with increasing of applied voltage. The dc conductivity has been measured for bulk polyaniline pure and doped in the form of compressed pellet with evaporated Ohmic Al electrodes in temperature range (303-423) K. The Eav energy of the thermal rate process of the electrical conductivity was determined. The results indicate that the dc conductivity of doped samples are two or t

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Publication Date
Sat Mar 11 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Electrical Conductivity and Hall Effect Measurements of (CuInTe2) Thin Films
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     In this research, the electrical conductivity and Hall effect measurements have been investigated on the CuInTe2 (CIT) thin films prepared by thermal evaporation technique on glass substrate at room temperature as a function of annealing temperature (R.T,473,673)K for different thicknesses (300 and 600) nm. The samples were annealed for one hour.    The electrical conductivity analysis results demonstrated that all samples prepared have two types of transport mechanisms of free carriers with two values of activation energy (Ea1, Ea2), and the electrical conductivity increases with the increase of annealing temperature whereas it showed opposite trend with thickness , where the electrical conductivity would d

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Publication Date
Mon May 01 2023
Journal Name
Cuadernos De Economía
The Role of Carbon Pricing Mechanisms and Renewable Energy Technologies in Reducing Carbon Emissions: Evidence from the International Economy
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Abstract: The international community now places significant emphasis on achieving zero carbon emissions, requiring both new researchers and experienced policymakers to prioritise this goal. This article examines the effects of carbon taxes, carbon cap and trade, renewable energy (RE) production and consumption, and economic growth (EG) on carbon emission reduction in the United States, Japan, Canada, and Australia. The study collected secondary data from the World Development Indicators (WDI) secondary source spanning the years 1991 to 2022. The study examines the relationship between variables using the cross-sectionally augmented autoregressive distributed lag (CS-ARDL) approach. The findings indicate that carbon taxes, carbon cap and tr

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Publication Date
Thu Apr 28 2022
Journal Name
Iraqi Journal Of Science
Preparation and Characterization of γ-Al2O3/Al Composite
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A cermet (ceramic-metal) composite have been prepared from alumina (γ-Al2O3) reinforced with aluminum (Al) for the concentrations of (0, 10, 20, 30, 40, & 50) wt. %Al. The cermet was formed by single axial pressing, sintered in vacuum atmosphere. Compaction behaviors were studied in solid state sintering at sintering temperatures (400, 450, & 550) °C, sintering times (2, 4, & 6) hrs., and forming pressures (5, 10, 15) MPa, also in liquid phase sintering at (800 °C). The cermet was characterized by x-ray diffraction (XRD) and by scanning electron microscope (SEM), also physical and mechanical properties have been studied. SEM results showed the Al flowing inside the ceramic body due to uniform distribution of Al particles a

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Publication Date
Sat Jun 27 2020
Journal Name
Iraqi Journal Of Science
Preparation and Characterization of Polymer Blends/ Kaolinite Nanoclay
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     In this research, we prepared a polymer blend of polyvinylalcohol (PVA)/carrageenan/kaolinite by means of the solution cast approach. The composition of the blend was PVA in 1 gm by weight with 0.2 gm carrageenan as a plasticizer. The ratio of nanoclay varied between 1 and 5 wt%. Different properties were investigated in this study such as water vapor permeability, hardness, tear strength, color stability, thermal stability, and antibacterial activity. Water vapor permeability was decreased with increasing the ratio of nanoclay, while the values of hardness, tear strength, color stability, and thermal stability were increased. Also, the antibacterial activity examination with two types of bacteria, e.g.

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Publication Date
Sat Apr 20 2019
Journal Name
Drug Invention Today
Preparation and evaluation of lornoxicam film-forming gel
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