Preparation of Gadolina Stabilized Bismuth Oxide Doped with Boron via Electrospinning Technique

In this study, boron doped and undoped poly (vinyl) alcohol/bismuth–gadolina acetate (PVA/Bi–Gd) nanofibers were prepared using electrospinning technique then calcinated at 800 °C for 2 h. The originality of this study is the addition of boron to metal acetates. The effects of boron doping were investigated in terms of solution properties, morphological changes and thermal characteristics. The characteristics of the fibers were investigated with FT-IR, XRD, SEM and BET. The addition of boron did not only increase the thermal stability of the fibers, but also their diameters, which yielded stronger fibers. XRD analyses showed that boron doping increased the peak intensities and indicated that the boron doping enhanced the crystallite size. Moreover, no shifts were noticed in diffraction angles for boron doped and undoped samples. Therefore, boron doping did not significantly alter the lattice spacing. The SEM micrograph of the fibers showed that the addition of boron resulted in the formation of cross-linked bright-surfaced fibers. The average fiber diameter for boron doped and undoped fiber mats were 204 and 123 nm, respectively. Also, grain diameters of boron doped and undoped nanocrystalline sintered powders were measured as 140 and 118 nm, respectively. The BET results showed that boron undoped and doped Bi₂O₃–La₂O₃ nanocrystalline powder ceramic structures sintered at 800 °C have surface areas of 59.72 and 39.80 m²/g, respectively.     

What is the Effect of Critical Surface Tension of PbSO3 Thin Film?

This study focuses on the critical surface tension of lead sulfite (PbSO₃) crystalline thin film produced with chemical bath deposition on substrates (commercial glass).The PbSO₃ thin films were deposited at room temperature at different deposition times. The structural properties of the films were defined and examined according to X-ray diffraction (XRD) and the XRD results such as dislocation density, average grain size, and no. of crystallites per unit area. Atomic force microscopy was used to measure the film thickness and the surface properties. The critical surface tension of the PbSO₃ thin films was measured with an optical tensiometer instrument and calculated using the Zisman method. The results indicated that the critical surface tension of films changed in accordance with the average grain size and film thickness. The film thickness increased with deposition time and was inversely correlated with surface tension. The average grain size increased according to deposition time and was inversely correlated with surface tension.     

The effects of the addition of corn husk fibre,kaolin and beeswax on cross-linked corn starch foam

Significant efforts have recently been made to improve the physical properties of starch foams formed using baking processes. For example, cross-linking starch with 0.126 g/kg glyoxal considerably reduces the baking time, density and water absorption of starch foams. In this study, we attempted to further develop the physical properties of glyoxal cross-linked starch foam by adding corn husk fibre, kaolin, beeswax and combinations of these products. We also studied the effects of these components on the microstructure and physicochemical and mechanical properties of trays. Starch-based trays in which additives were used showed improved water resistance. The water absorption capacities of the trays were 13%, 14% and 9% when combinations of kaolin/beeswax, fibre/beeswax and fibre/kaolin/beeswax were added, respectively.     

Yellowing tendency of ozonated cotton fabric and ways to prevent this undesirable side effect

This paper provides a general framework for studying the yellowing tendency of ozonated cotton fabric. Yellowing tendency of ozonated cotton fabric and ways to prevent this situation was examined extensively. For this purpose, five different treatments (hot/cold rinsing, washing, reductive washing, catalase treatment) were performed after ozonation. It was found that performing any kind of treatment was significantly important for preventing yellowing of ozonated cotton fabric during storage.     

Artificial neural networks solution to display residual hoop stress field encircling a split-sleeve cold expanded aircraft fastener hole

Cold expansion of holes is a technique, generating intricate three-dimensional residual stresses around fastener holes essentially vital for airplane fatigue resistance. In this work, attention was given to Artificial Neural Networks (ANN) modeling to build up and train simulations of stress topography surrounding a 4% expanded hole. For this, experimental data of recently abridged step drilling-Fourier method was employed. At input layer of ANN; information available for steps through thickness and radial directions, angular variation around the hole, and at output layer, residual hoop stresses were exercised to train and test multilayered, hierarchically connected and directed networks with varying number of hidden layers. It was shown that Levenberg–Marquardt (LM) model with 9 neurons in hidden layer yielded the best of the results, as error percentages were remarkably small both in training and testing sequences. Several results of step drilling-Fourier solution (ATÖzdemir method), diffraction methods and current ANN predictions were overlaid and similarities in residual stress distributions perceived to valid only at regions where strain gradient was not changing precipitously. Nevertheless, best fit to strain data at confusing zones was achieved after ANN modeling.     

Synthesis and characterization of neodymium doped ceria nanocrystalline ceramic structures

In this study, a new method to synthesize neodymium doped ceria ceramic nanopowders by the electrospinning of the hybrid polymers solution of their composite precursor was put forward. Calcined and sintered nanopowders were characterized by FT-IR, XRD, BET, SEM, and AFM techniques. According to the XRD analysis, the obtained powders are single phase and independent of the dopant concentration in the range investigated. The crystallite sizes were calculated using Scherrer equation. Moreover, lattice parameters, dislocation densities and microstrain values were calculated. BET results show that the increase of the neodymium doped content decrease the surface area of the composite powders, confirming the highly ordered micro and mesostructure. SEM and AFM results show that the samples have spherical grains. According to the surface roughness measurements, the increase in the amount of neodymium and the decrease in the amount of cerium decreased the surface roughness.