Comparison of the internet usage levels amongst final year students of faculty of medicine and health colleges in Turkey: According to the gender variable

The use of internet is becoming widespread all over the world including the health sector. Internet has been increasing its importance for individuals in the health sector for purposes of increasing speed and efficiency of surgeries, sharing patients’ data, storing information in the database. The aim of this study is to examine the relationship between a group of medicine faculty and health college students’ level of internet use and their views about the internet with regard to their gender. The final year students of the faculty of medicine and health college at F?rat University constituted the sample of the research. Of 219 final year students, 155 students who were present when the research was conducted constituted the sample of this study. A Likert type questionnaire was used to determine students’ level of internet use. The questionnaire was developed previously by the researcher and the test of its reliability and validity was performed. The study reveals that 14.8% of the students use internet for 2 h or more in a week and 72.9% of students do not use internet in weekdays at all. The findings also showed that 76.1% of the students know the concept of ‘internet’ for more than four years, and 61.9% of the students access to internet from the internet cafes, 48.4% of the students use internet for academic purposes and 63.9% of the students want to set up their web pages on the internet. In the light of research findings, it is thought that internet-based and interactive lesson applications are inevitable education tools for education faculties of medicine and health colleges in the future. According to the findings, female students seem to log into internet less but stay connected more, and students mostly prefer to use internet cafes for internet access. In these cafes, internet is used mainly for academic purposes. It is expected that this study will provide some educational implications that enable effective use of internet in health education and a cooperative learning environment that would allow male and female students to study collaboratively.     

Preparation of dendritic waterborne polyurethane-urea/Ni–Zn ferrite composite coatings and investigation of their microwave absorption properties

This study shows the preparation of microwave absorbing composite material by using Ni–Zn ferrite filler and dendritic waterborne polyurethane-urea (WPU) polymer as a matrix. Initially, waterborne polyurethane prepolymers were synthesized by using PEG1500 (WPU1) and PPG1000 (WPU2) polyols via prepolymer mixing process. Then, chain extended with water in the presence of hexamethylenetetramine (HMTA) as crosslinker. Then, 1/1 (w/w) amount of Ni–Zn ferrite was dispersed in the WPU polymer to be converted into a microwave absorbing composite coating (CWPU1 and CWPU2). Structural, mechanical and morphological properties were investigated. The microwave absorption measurements were performed by using transmission/reflection method via waveguide method in the frequency range of 8.2–12.4 GHz. Permittivity and permeability measurements were performed in the frequency range of 8.2–12.4 GHz. It has been found that CWPU1 which was prepared by using WPU1 polymer indicated broader microwave absorption between 9.4 and 11.7 GHz due to its dendritic structure. Besides, permittivity and permeability results indicated that CWPU1 and CWPU2 have distinctive magnetic properties.     

An alternative approach for calculating/measuring fundamental powers based on wavelet packet transform and its frequency sensitivity analysis

Power and harmonic analysis are among the most important topics of power systems. These analyses usually are based on Fourier transform method. In this study, as a novel approximation, the accuracy of proposed method using wavelet packet transform for fundamental active-reactive-apparent powers, displacement power factor are pointed out with computer simulations. Moreover, frequency sensitivity of the wavelet packet based power analysis, any study concerned with it is not found in the literature up to now, is carried out in comparison with the classic Fourier-based analysis. The results show the supremacy of the proposed wavelet packet-based approach over the Fourier-based approach when the frequency variation is concerned.     

Flame retardancy behaviors and structural properties of polypropylene/nano‐SiO2 composite textile filaments

The number of efforts about modifying the properties of polymeric fibers by organic or inorganic particles has increased recently because of high‐tech applications of textiles. In addition to these attempts, the discovery of nanotechnology also leads to the development of nanoparticles for various end uses such as nanocomposite fibers. In this article, we aimed to produce slow burning or flame retardant polypropylene filaments for carpet pile yarns by incorporating SiO₂ nanoparticles into polymer. Therefore, we present the preparation of filaments incorporating 0.3, 1, and 3% SiO₂ nanoparticles and investigate the effects of nanoparticles on the flame retardancy and structural behavior of filaments. Polypropylene and nanoparticles were compounded by melt‐compounding using twin‐screw extruder before spinning. Filaments with trilobal cross sections were spun using pilot melt spinning equipment. The structural properties of nanocomposite fibers were analyzed using X‐ray difractometry, differential scanning calorymetry, scanning electron microscopy, and tensile tests. The flammability behaviors of filaments were evaluated using the oxygen index method. The effect of nanoparticles on structural properties and flame retardancy behaviors of filaments were summarized and discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Melt immiscibility in crosslinked polyethylene

Low density polyethylene crosslinked by decomposition of dicumyl peroxide shows evidence for two phases being present in the melt in a narrow temperature range just above the melting point. The effect has been studied in detail using differential scanning calorimetry, transmitted light intensity, and wide angle X-ray diffraction studies at 107°C. It is believed that the effect is caused by the presence of relatively low molecular weight molecules which remain as an extractable fraction after crosslinking.     

Forecasting Ambient Air SO2 Concentrations Using Artificial Neural Networks

An Artificial Neural Networks (ANNs) model is constructed to forecast SO₂ concentrations in Izmir air. The model uses meteorological variables (wind speed and temperature) and measured particulate matter concentrations as input variables. The correlation coefficient between observed and forecasted concentrations is 0.94 for the network that uses all three variables as input parameters. The root mean square error value of the model is 3.60 μg/mt³. Considering the limited number of available input variables, model performances show that ANNs are a promising method of modeling to forecast ambient air SO₂ concentrations in Izmir.     

Buckling Characteristics of Symmetrically and Antisymmetrically Laminated Composite Plates with Central Cutout

A numerical and experimental study was carried out to determine the effects of anti-symmetric laminate configuration, cutout and length/thickness ratio on the buckling behavior of E/glass-epoxy composite plates. The buckling loads were presented for symmetrically and anti-symmetrically laminated plates subjected to axial compression load. The study included two different laminate configurations ([90/45/−45/0]_as and [90/45/−45/0]_s), two different cutout shapes (circular and semi-circular), two different length/thickness ratios (L/t = 75 and 37.5) and three boundary conditions (clamped–clamped [CC], clamped–pinned [CP] and pinned–pinned [PP]). Firstly, the buckling loads of eight-ply E/glass-epoxy rectangular plates were determined experimentally. Then, the buckling loads of the laminated composites were calculated by ANSYS finite-element computer code. The changing in buckling load of the composites due to the presence of cutout and changing of length/thickness ratio was calculated. Finally, the experimental test results were compared to the buckling loads of plates obtained from the finite element analysis.     

Experimental characterization and morphology investigation of composites based on high‐density and low‐density polyethylene reinforced with non‐crimp‐stitched glass fabrics

In this study, the effects of matrix material on mechanical properties were investigated in glass fiber reinforced high‐density and low‐density polyethylene composites. Also, in order to compare the fiber configuration effect on anisotropic behavior, unidirectional and biaxial glass fabrics were used as reinforcement material. Composite laminates were manufactured via the compression molding technique. Tensile and three‐point bending flexural tests were conducted up to failure on specimens cut out in different directions. Extensive fracture photomicrographs were presented for observing the failure modes (e.g. delamination) of the composites resulting from a variety of loading conditions. In addition, Scanning electron micrographs of postfractured surfaces of composites were interpreted in an attempt to explain the failure mechanisms (adhesive or cohesive failure) of the composites. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

LC–MS/MS characterization,antidiabetic, antioxidative,and antibacterial effects of different solvent extracts of Anamur banana (Musa Cavendishii)

The main objective of this study was to examine the phenolic compounds and the antibacterial, antioxidant, anti-α-glucosidase and anti-α-amylase activities of the different extracts (methanol, ethanol and hexane) of Musa cavendishii collected from the Anamur district in Turkey. LC–MS/MS was used to identify phenolic compounds. Quinic acid, acotinic acid, hesperidin and amentoflavone were identified in methanol extract. These phenolic compounds, excluding hesperidin, were also identified in the ethanol extract. Methanolic extract appeared the most active in all enzyme inhibition, antibacterial and antioxidative activity assays which is mainly due to its rich phenolic content. The methanol extract of banana showed the highest anti-α-glucosidase and anti-α-amylase activities with IC50 values of 5.45 ± 0.39 mg/mL, 9.70 ± 0.29 mg/mL, respectively. This study showed that methanol and ethanol extract, especially the methanol extract, have potential for use in the development of functional foods for reducing the diabetes and bacterial risks.     

Synthesis of poly(butyl acrylate‐co‐methyl methacrylate)/montmorillonite waterborne nanocomposite via semibatch emulsion polymerization

Poly(butyl acrylate‐co‐methyl methacrylate)‐montmorillonite (MMT) waterborne nanocomposites were successfully synthesized by semibatch emulsion polymerization. The syntheses of the nanocomposites were performed in presence of sodium montmorillonite (Na‐MMT) and organically modified montmorillonite (O‐MMT). O‐MMT was used directly after the modification of Na‐MMT with dimethyl dioctadecyl ammonium chloride. Both Na‐MMT and O‐MMT were sonified to obtain nanocomposites with 47 wt % solids and 3 wt % Na‐MMT or O‐MMT content. Average particle sizes of Na‐MMT nanocomposites were measured as 110–150 nm while O‐MMT nanocomposites were measured as 200–350 nm. Both Na‐MMT and O‐MMT increased thermal, mechanical, and barrier properties (water vapor and oxygen permeability) of the pristine copolymer explicitly. X‐ray diffraction and transmission electron microscope studies show that exfoliated morphology was obtained. The gloss values of O‐MMT nanocomposites were found to be higher than that of the pristine copolymer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42373.