4,588 research outputs found

    Preparation and Characterization of Titanium Dioxide (TiO ) Thin Films Prepared By Spin Coating Method 2

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    Transparent semiconducting thin films of titanium dioxide (TiO 2 - ) were deposited on glass substrates by spincoating technique and with thickness was in order of 15

    Preparation and Characterization of Titanium Dioxide (TiO ) Thin Films Prepared By Spin Coating Method 2

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    Transparent semiconducting thin films of titanium dioxide (TiO 2 - ) were deposited on glass substrates by spincoating technique and with thickness was in order of 150 Ā± 5 nm . The XRD analysis reveals that the films are polycrystalline with an anatase crystal structure and a preferred grain orientation in the (101) direction. The optical properties of the films were characterized by UVā€“visible spectrophotometry, which shows that the films are highly transparent in the visible and near infrared , with an average value above (99 %), with energy gape (3.79 e.v ). The dependence of the refractive index (n), extinction coefficient (k), and absorption coefficient (Ī±) of the films on the wavelength was investigated

    PVA/Chitosan/Silver Nanoparticles Electrospun Nanocomposites: Molecular Relaxations Investigated by Modern Broadband Dielectric Spectroscopy

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    In this study, we used broadband dielectric spectroscopy to analyze polymer nanofibers of poly(vinyl alcohol)/chitosan/silver nanoparticles. We also studied the effect of incorporating silver nanoparticles in the polymeric mat, on the chain motion dynamics and their interactions with chitosan nanofibers, and we calculated the activation energies of the sub-Tg relaxation processes. Results revealed the existence of two sub-Tg relaxations, the first gets activated at very low temperature (āˆ’90 Ā°C) and accounts for motions of the side groups within the repeating unit such as ā€“NH2, ā€“OH, and ā€“CH2OH in chitosan and poly(vinyl alcohol). The second process gets activated around āˆ’10 Ā°C and it is thought to be related to the local main chain segmentsā€™ motions that are facilitated by fluctuations within the glycosidic bonds of chitosan. The activation energy for the chitosan/PVA/AgNPs nanocomposite nanofibers is much higher than that of the chitosan control film due to the presence of strong interactions between the amine groups and the silver nanoparticles. Kramersā€“Krƶnig integral transformation of the Īµā€²ā€² vs. f spectra in the region of the chitosan Tg helped resolve this relaxation and displayed the progress of its maxima with increasing temperature in the regular manner

    Fabrication of (Polymer Blend-magnesium Oxide) Nanoparticle and Studying their Optical Properties for Optoelectronic Applications

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    Nanocomposites used in many optical devices applications. This aims to preparation of new type of polymer and study their optical properties. The polyvinyl pyrrolidone-carboxymethyl cellulose blend and magnesium oxide nanocomposites have been fabricated. The nanocomposites are prepared for different concentrations of polymer blend and magnesium oxide nanoparticles. The optical properties of nanocomposites were studied. The experimental results showed that the absorbance, absorption coefficient, refractive index, extinction coefficient, real and imaginary parts of dielectric constant and optical conductivity of (PVP-CMC) blend are increased with increase of the MgO nanoparticles concentration. The transmittance and energy band gap are decreased with increase of the MgO nanoparticles concentration. The nanocomposites have high absorbance in UV region which may be used for radiation shielding application

    Passive smoking in the etiology of non-syndromic orofacial clefts:a systematic review and meta-analysis

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    Background Studies have found a consistent positive association between maternal smoking and nonsyndromic orofacial clefts (NSOFC). However, no comprehensive assessment of the association between NSOFC and passive smoking has been undertaken. This systematic review and meta-analysis explores the relationship between maternal passive smoking and NSOFC, and compares the associations between passive and active smoking. Methods and Findings Search strategy, inclusion / exclusion criteria, and data extraction from studies reporting maternal passive smoking and NSOFC was implemented without language restrictions. Risks of bias in the identified studies were assessed and this information was used in sensitivity analyses to explain heterogeneity. Meta-analysis and meta-regression of the extracted data were performed. Egger's test was used to test for small study effects. Fourteen eligible articles were identified. Maternal passive smoking exposure was associated with a twofold increase in risk of NSOFC (odds ratio: 2.11, 95% confidence interval: 1.54-2.89); this was apparent for both cleft lip with and without palate (OR: 2.05, 95% CI: 1.27-3.3) and cleft palate (OR: 2.11, 95% CI: 1.23-3.62). There was substantial heterogeneity between studies. In the studies that provided data enabling crude and adjusted odd ratios to be compared, adjustment for potential confounders attenuated the magnitude of association to about a 1.5-fold increase in risk. Conclusion Overall, maternal passive smoking exposure results in a 1.5 fold increase in risk of NSOFC, similar to the magnitude of risk reported for active smoking, but there is marked heterogeneity between studies. This heterogeneity is not explained by differences in the distribution of cleft types, adjustment for covariates, broad geographic region, or study bias/quality. This thorough meta-analysis provides further evidence to minimize exposure to environmental tobacco smoke in policy making fora and in health promotion initiatives.</p

    Integration of TTF, UTAUT, and ITM for mobile Banking Adoption

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    The introduction of mobile banking facility has enabled customers to carry out banking transactionswith the use of smartphones and other handheld devices from anywhere. It has become a luxurious and exclusive method of online payments. The recent growth of telecommunication sector and a tremendous increase in mobile USAge has opened new doors for sparking future of banking sector industry. The following research is aimed to find out the mobile banking adoption attitudes with the integration of TTF, UTAUT,and ITM models

    Polymer chain dynamics in epoxy based composites as investigated by broadband dielectric spectroscopy

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    Epoxy networks of the diglycidyl ether of bisphenol A (DGEBA) were prepared using 3,3ā€²- and 4,4ā€²-diaminodiphenyl sulfone isomer crosslinkers. Secondary relaxations and the glass transitions of resultant networks were probed using broadband dielectric spectroscopy (BDS). A sub-TgĪ³ relaxation peak for both networks shifts to higher frequencies (f) with increasing temperature in Arrhenius fashion, both processes having the same activation energy and being assigned to phenyl ring flipping in DGEBA chains. A Ī² relaxation is assigned to local motions of dipoles that were created during crosslinking reactions. 4,4ā€²-based networks exhibited higher Tg relative to 3,3ā€²-based networks as per dynamic mechanical as well as BDS analyses. The Vogelā€“Fulcherā€“Tammannā€“Hesse equation fitted well to relaxation time vs. temperature data and comparison of Vogel temperatures suggests lower free volume per mass for the 3,3ā€²-based network. The Kramersā€“Krƶnig transformation was used to directly calculate dc-free ɛā€³ vs. f data from experimental ɛā€² vs. f data. Distribution of relaxation times (DRT) curves are bi-modal for the 3,3ā€²-crosslinked resin suggesting large-scale microstructural heterogeneity as opposed to homogeneity for the 4,4ā€²-based network whose DRT consists of a single peak.U.S. Office of Naval Research, Award N00014-07-1-1057 and fellowship support from the Department of Education Graduate Assistance in Areas of National Need Award P200A090066. Qatar University's Center for Advanced Materials' Start-Up grant

    Host genetic susceptibility to mycetoma

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    Mycetoma is one of the badly neglected tropical diseases characterised by subcutaneous painless swelling, multiple sinuses and discharge containing aggregates of the infecting organism known as grains. Risk factors conferring susceptibility to mycetoma include environmental factors, pathogen factors such as virulence and the infecting dose in addition to host factors such as immunological and genetic predisposition. Epidemiological evidence suggests that host genetic factors may regulate susceptibility to mycetoma and other fungal infections but they are likely to be complex genetic traits where multiple genes interact with each other and environmental factors, as well as the pathogen, to cause disease. This paper reviews what is known about genetic predisposition to fungal infections that might be relevant to mycetoma as well as all studies carried out to explore host genetic susceptibility to mycetoma. Most studies were investigating polymorphisms in candidate genes related to the host immune response. A total of 13 genes had allelic variants found to be associated with mycetoma and these genes lie in different pathways and systems such as innate and adaptive immune systems, sex hormones biosynthesis and some genes coding for host enzymes. None of these studies have been replicated. Advances in genomic science and the supporting technology have paved the way for large-scale genome-wide association and next generation sequencing (NGS) studies, underpinning a new strategy to systematically interrogate the genome for variants associated with mycetoma. Dissecting the contribution of host genetic variation to susceptibility to mycetoma will enable the identification of pathways that are potential targets for new treatments for mycetoma and will also enhance the ability to stratify ā€œat-riskā€ individuals allowing the possibility to develop preventive and personalised clinical care strategies in the future

    A methodology for flexibility analysis of pipeline systems

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    Pipeline systems serve a crucial role in an effective transport of fluids to the designated location for medium to long span of distances. Owing to its paramount economic significance, pipeline design field have undergone extensive development over the past few years for enhancing the optimization and transport efficiency. This research paper attempts to propose a methodology for flexibility analysis of pipeline systems through employing contemporary computational tools and practices. A methodical procedure is developed, which involves modeling of the selected pipeline system in CAESAR II followed by the insertion of pipe supports and restraints. The specific location and selection of the inserted supports is based on the results derived from the displacement, stress, reaction, and nozzle analysis of the concerned pipeline system. Emphasis is laid on the compliance of the design features to the leading code of pipeline transportation systems for liquid and slurries, ASME B31.4. The discussed procedure and approach can be successfully adjusted for the analysis of various other types of pipeline system configuration. In addition to the provision of systematic flow in analysis, the method also improves efficient time-saving practices in the pipeline stress analysis
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