The influence of Cr3+ doping on the ground state properties of SrTiO3 perovskite was evaluated using GGA-PBE approximation. Computational modeling results infered an agreement with the previously published literature. The modification of electronic structure and optical properties due to Cr3+ introducing into SrTiO3 were investigated. Structural parameters assumed that Cr3+ doping alters the electronic structures of SrTiO3 by shifting the conduction band through lower energies for the Sr and Ti sites. Besides, results showed that the band gap was reduced by approximately 50% when presenting one Cr3+ atom into the SrTiO3 system and particularly positioned at Sr sites. Interestingly, substituting Ti site by Cr3+ led to eliminating the band gap indicated a new electrical case of transferring semiconducting material into a conducting material which intern enhance conductivity. Furthermore, it was found that Cr3+ doping either at Sr or Ti positions could effectively develop the SrTiO3 dielectric constant properties. In addition, the absorption spectra was extended to cover the visible light region of the electromagnetic radiation, indicating the capability of this compound in harvesting sunlight for solar cell applications. Consequently, it can be said that Cr3+ is an effective dopant which opening up new prospects for various industrial and technological applications.
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 form
The main aim of this study is to assess the performance and residual strength of post-fire non-prismatic reinforced concrete beams (NPRC) with and without openings. To do this, nine beams were cast and divided into three major groupings. These groups were classified based on the degrees of heating exposure temperature chosen (ambient, 400, and 700°C), with each group containing three non-prismatic beams (solid, 8 trapezoidal openings, and 8 circular openings). Experimentally, given the same beam geometry, increasing burning temperature caused degradation in NPRC beams, which was reflected in increased mid-span deflection throughout the fire exposure period and also residual deflectio
Coumarin derivatives have shown different biological activities, such as antifungal, antibacterial antiinflammatory, and antioxidant activities, besides antibiotic resistance modulating effects, and anti-HIV, hepatoprotective, and antitumor effect. So, new coumarin derivatives (hydrazones and an amide) were synthesized through multisteps reactions. All the synthesized target compounds were characterized by FT-IR spectroscopy, 1HNMR analysis. The compounds then evaluated for their anti-bacterial activity by means of well-diffusion method against two gram-positive bacteria (Staphylococcus aureus, Streptococcus pneumoniae) and two gram-negative bacteria (E.coli and Pseudomonas aeruginosa). The highest activity was demonstr
... Show MoreEmily Bronte is born in Yorkshire on 30 July 1818. Her father, Rev. Patrick Bronte, is a man of intelligence and determination which enables him to gain an admission as a sizar to 81. John's Cambridge in 1802. He has six children where Emily is the fifth. The mother is a young beautiful girl who belong to an important family. Both Emily's parents try to teach
Their children well, support them all the time and elevate them to
"-.../
high levels. This causes an eagerness towards reading and writing, but the happiness of the children is affected by the sickness and later on by the death of their mother in 1821. After that things would
... Show MoreObjective: A descriptive design, using the methodological approach, is carried throughout the present
study from April 1st 2012 to May 20th 2013 to construct the school physical environment standardized
features tool.
Methodology: An instrument of (141) item is constructed for the purpose of the study. A purposive
sample of (44) school; (22) public and (22) private ones is selected. Content Validity of the instrument is
determined through the use of panel of (11) expert who are specialists in Community Health Nursing and
Community Medicine. Internal consistency reliability, using the split-half technique, is employed through
the computation of Cronbach alpha correlation coefficient of (0.93) for internal scale. Data
The current research is concerned with the study of (aesthetic discourse in the significance of commercial advertisement designs), according to a knowledge structure defined by function and creativity, and the main goal is to interpret the reality of forms, their various sources, their essence, meanings, formal relationships, and design ideas in order to achieve the visual goal as a typographic achievement. It arises through the designer’s internal mental intuition to produce shapes based on subjective feelings that refer his preconceptions about those shapes with his feelings to creative formations. Aesthetic discourse is produced from the mind depending on the various symbolic, psychological and social functions, production methods,
... Show MoreObjective: The aim of the study is to assess the personal hygiene of adult patients with
diabetic foot.
Methodology: ٨ descriptive study was carried out in Baghdad teaching hospital, Al-Karama teaching hospital
and Al-Kindey teaching hospital for the period of 10/1/2006 to 1/9/2006. A purposive "non probability" sample
of (100) patient.
Questionnaire was constructed for achieving the purpose of the study. Data were collected through the
application of the questionnaire and interview technique. Data were analyzed through descriptive statistical
approach (frequency & percentage) and inferential statistical approach (chi-square ع correlation) by using of
SPSS.
Results: The study results indicated that the ra